SCREEN(1) General Commands Manual SCREEN(1)
NAME
screen - screen manager with VT100/ANSI terminal emulation
SYNOPSIS
screen [ -options ] [ cmd [ args ] ]
screen -r [[pid.]tty[.host]]
screen -r sessionowner/[[pid.]tty[.host]]
DESCRIPTION
Screen is a full-screen window manager that multiplexes a physical ter-
minal between several processes (typically interactive shells). Each
virtual terminal provides the functions of a DEC VT100 terminal and, in
addition, several control functions from the ISO 6429 (ECMA 48, ANSI
X3.64) and ISO 2022 standards (e.g. insert/delete line and support for
multiple character sets). There is a scrollback history buffer for each
virtual terminal and a copy-and-paste mechanism that allows moving text
regions between windows.
When screen is called, it creates a single window with a shell in it (or
the specified command) and then gets out of your way so that you can use
the program as you normally would. Then, at any time, you can create
new (full-screen) windows with other programs in them (including more
shells), kill existing windows, view a list of windows, turn output log-
ging on and off, copy-and-paste text between windows, view the scroll-
back history, switch between windows in whatever manner you wish, etc.
All windows run their programs completely independent of each other.
Programs continue to run when their window is currently not visible and
even when the whole screen session is detached from the user's terminal.
When a program terminates, screen (per default) kills the window that
contained it. If this window was in the foreground, the display
switches to the previous window; if none are left, screen exits. Shells
usually distinguish between running as login-shell or sub-shell. Screen
runs them as sub-shells, unless told otherwise (See shell .screenrc com-
mand).
Everything you type is sent to the program running in the current win-
dow. The only exception to this is the one keystroke that is used to
initiate a command to the window manager. By default, each command be-
gins with a control-a (abbreviated C-a from now on), and is followed by
one other keystroke. The command character and all the key bindings can
be fully customized to be anything you like, though they are always two
characters in length.
Screen does not understand the prefix C- to mean control, although this
notation is used in this manual for readability. Please use the caret
notation (^A instead of C-a) as arguments to e.g. the escape command or
the -e option. Screen will also print out control characters in caret
notation.
The standard way to create a new window is to type C-a c. This creates
a new window running a shell and switches to that window immediately,
regardless of the state of the process running in the current window.
Similarly, you can create a new window with a custom command in it by
first binding the command to a keystroke (in your .screenrc file or at
the C-a : command line) and then using it just like the C-a c command.
In addition, new windows can be created by running a command like:
screen emacs prog.c
from a shell prompt within a previously created window. This will not
run another copy of screen, but will instead supply the command name and
its arguments to the window manager (specified in the $STY environment
variable) who will use it to create the new window. The above example
would start the emacs editor (editing prog.c) and switch to its window.
- Note that you cannot transport environment variables from the invoking
shell to the application (emacs in this case), because it is forked from
the parent screen process, not from the invoking shell.
If /run/utmp is writable by screen, an appropriate record will be writ-
ten to this file for each window, and removed when the window is termi-
nated. This is useful for working with talk, script, shutdown, rsend,
sccs and other similar programs that use the utmp file to determine who
you are. As long as screen is active on your terminal, the terminal's
own record is removed from the utmp file. See also C-a L.
GETTING STARTED
Before you begin to use screen you'll need to make sure you have cor-
rectly selected your terminal type, just as you would for any other
termcap/terminfo program. (You can do this by using test for example.)
If you're impatient and want to get started without doing a lot more
reading, you should remember this one command: C-a ?. Typing these two
characters will display a list of the available screen commands and
their bindings. Each keystroke is discussed in the section DEFAULT KEY
BINDINGS. The manual section CUSTOMIZATION deals with the contents of
your .screenrc.
If your terminal is a true auto-margin terminal (it doesn't allow the
last position on the screen to be updated without scrolling the screen)
consider using a version of your terminal's termcap that has automatic
margins turned off. This will ensure an accurate and optimal update of
the screen in all circumstances. Most terminals nowadays have magic mar-
gins (automatic margins plus usable last column). This is the VT100
style type and perfectly suited for screen. If all you've got is a true
auto-margin terminal screen will be content to use it, but updating a
character put into the last position on the screen may not be possible
until the screen scrolls or the character is moved into a safe position
in some other way. This delay can be shortened by using a terminal with
insert-character capability.
COMMAND-LINE OPTIONS
Screen has the following command-line options:
-a include all capabilities (with some minor exceptions) in each win-
dow's termcap, even if screen must redraw parts of the display in
order to implement a function.
-A Adapt the sizes of all windows to the size of the current terminal.
By default, screen tries to restore its old window sizes when at-
taching to resizable terminals (those with WS in its description,
e.g. suncmd or some xterm).
-c file
override the default configuration file from $HOME/.screenrc to
file.
-d|-D [pid.tty.host]
does not start screen, but detaches the elsewhere running screen
session. It has the same effect as typing C-a d from screen's con-
trolling terminal. -D is the equivalent to the power detach key.
If no session can be detached, this option is ignored. In combina-
tion with the -r/-R option more powerful effects can be achieved:
-d -r Reattach a session and if necessary detach it first.
-d -R Reattach a session and if necessary detach or even create it
first.
-d -RR Reattach a session and if necessary detach or create it. Use the
first session if more than one session is available.
-D -r Reattach a session. If necessary detach and logout remotely
first.
-D -R Attach here and now. In detail this means: If a session is run-
ning, then reattach. If necessary detach and logout remotely
first. If it was not running create it and notify the user.
This is the author's favorite.
-D -RR Attach here and now. Whatever that means, just do it.
Note: It is always a good idea to check the status of your sessions
by means of screen -list.
-e xy
specifies the command character to be x and the character generat-
ing a literal command character to y (when typed after the command
character). The default is C-a and `a', which can be specified as
-e^Aa. When creating a screen session, this option sets the de-
fault command character. In a multiuser session all users added
will start off with this command character. But when attaching to
an already running session, this option changes only the command
character of the attaching user. This option is equivalent to ei-
ther the commands defescape or escape respectively.
-f, -fn, and -fa
turns flow-control on, off, or automatic switching mode. This can
also be defined through the defflow .screenrc command.
-h num
Specifies the history scrollback buffer to be num lines high.
-i will cause the interrupt key (usually C-c) to interrupt the display
immediately when flow-control is on. See the defflow .screenrc
command for details. The use of this option is discouraged.
-l and -ln
turns login mode on or off (for /run/utmp updating). This can also
be defined through the deflogin .screenrc command.
-ls [match]
-list [match]
does not start screen, but prints a list of pid.tty.host strings
and creation timestamps identifying your screen sessions. Sessions
marked `detached' can be resumed with screen -r. Those marked `at-
tached' are running and have a controlling terminal. If the session
runs in multiuser mode, it is marked `multi'. Sessions marked as
`unreachable' either live on a different host or are `dead'. An
unreachable session is considered dead, when its name matches ei-
ther the name of the local host, or the specified parameter, if
any. See the -r flag for a description how to construct matches.
Sessions marked as `dead' should be thoroughly checked and removed.
Ask your system administrator if you are not sure. Remove sessions
with the -wipe option.
-L tells screen to turn on automatic output logging for the windows.
-Logfile file
By default logfile name is screenlog.0. You can set new logfile
name with the -Logfile option.
-m causes screen to ignore the $STY environment variable. With screen
-m creation of a new session is enforced, regardless whether screen
is called from within another screen session or not. This flag has
a special meaning in connection with the `-d' option:
-d -m Start screen in detached mode. This creates a new session but
doesn't attach to it. This is useful for system startup scripts.
-D -m This also starts screen in detached mode, but doesn't fork a new
process. The command exits if the session terminates.
-O selects an optimal output mode for your terminal rather than true
VT100 emulation (only affects auto-margin terminals without `LP').
This can also be set in your .screenrc by specifying `OP' in a
termcap command.
-p number_or_name|-|=|+
Preselect a window. This is useful when you want to reattach to a
specific window or you want to send a command via the -X option to
a specific window. As with screen's select command, - selects the
blank window. As a special case for reattach, = brings up the win-
dowlist on the blank window, while a + will create a new window.
The command will not be executed if the specified window could not
be found.
-q Suppress printing of error messages. In combination with -ls the
exit value is as follows: 9 indicates a directory without sessions.
10 indicates a directory with running but not attachable sessions.
11 (or more) indicates 1 (or more) usable sessions. In combination
with -r the exit value is as follows: 10 indicates that there is no
session to resume. 12 (or more) indicates that there are 2 (or
more) sessions to resume and you should specify which one to
choose. In all other cases -q has no effect.
-Q Some commands now can be queried from a remote session using this
flag, e.g. screen -Q windows. The commands will send the response
to the stdout of the querying process. If there was an error in the
command, then the querying process will exit with a non-zero sta-
tus.
The commands that can be queried now are:
echo
info
lastmsg
number
select
time
title
windows
-r [pid.tty.host]
-r sessionowner/[pid.tty.host]
resumes a detached screen session. No other options (except combi-
nations with -d/-D) may be specified, though an optional prefix of
[pid.]tty.host may be needed to distinguish between multiple de-
tached screen sessions. The second form is used to connect to an-
other user's screen session which runs in multiuser mode. This in-
dicates that screen should look for sessions in another user's di-
rectory. This requires setuid-root.
-R resumes screen only when it's unambiguous which one to attach, usu-
ally when only one screen is detached. Otherwise lists available
sessions. -RR attempts to resume the youngest (in terms of cre-
ation time) detached screen session it finds. If successful, all
other command-line options are ignored. If no detached session ex-
ists, starts a new session using the specified options, just as if
-R had not been specified. The option is set by default if screen
is run as a login-shell (actually screen uses -xRR in that case).
For combinations with the -d/-D option see there. Note: Time-based
session selection is a Debian addition.
-s program
sets the default shell to the program specified, instead of the
value in the environment variable $SHELL (or /bin/sh if not de-
fined). This can also be defined through the shell .screenrc com-
mand. See also there.
-S sessionname
When creating a new session, this option can be used to specify a
meaningful name for the session. This name identifies the session
for screen -list and screen -r actions. It substitutes the default
[tty.host] suffix. This name should not be longer then 80 symbols.
-t name
sets the title (a.k.a.) for the default shell or specified program.
See also the shelltitle .screenrc command.
-T term
Set the $TERM environment variable using the specified term as op-
posed to the default setting of screen.
-U Run screen in UTF-8 mode. This option tells screen that your termi-
nal sends and understands UTF-8 encoded characters. It also sets
the default encoding for new windows to `utf8'.
-v Print version number.
-wipe [match]
does the same as screen -ls, but removes destroyed sessions instead
of marking them as `dead'. An unreachable session is considered
dead, when its name matches either the name of the local host, or
the explicitly given parameter, if any. See the -r flag for a de-
scription how to construct matches.
-x Attach to a not detached screen session. (Multi display mode).
Screen refuses to attach from within itself. But when cascading
multiple screens, loops are not detected; take care.
-X Send the specified command to a running screen session. You may use
the -S option to specify the screen session if you have several
screen sessions running. You can use the -d or -r option to tell
screen to look only for attached or detached screen sessions. Note
that this command doesn't work if the session is password pro-
tected.
-4 Resolve hostnames only to IPv4 addresses.
-6 Resolve hostnames only to IPv6 addresses.
DEFAULT KEY BINDINGS
As mentioned, each screen command consists of a C-a followed by one
other character. For your convenience, all commands that are bound to
lower-case letters are also bound to their control character counter-
parts (with the exception of C-a a; see below), thus, C-a c as well as
C-a C-c can be used to create a window. See section CUSTOMIZATION for a
description of the command.
The following table shows the default key bindings. The trailing commas
in boxes with multiple keystroke entries are separators, not part of the
bindings.
──────────────────────────────────────────────────────────
C-a ' (select) Prompt for a window
name or number to
switch to.
──────────────────────────────────────────────────────────
C-a " (windowlist -b) Present a list of
all windows for se-
lection.
──────────────────────────────────────────────────────────
C-a digit (select 0-9) Switch to window
number 0 - 9
──────────────────────────────────────────────────────────
C-a - (select -) Switch to window
number 0 - 9, or to
the blank window.
──────────────────────────────────────────────────────────
C-a tab (focus) Switch the input fo-
cus to the next re-
gion. See also
split, remove, only.
──────────────────────────────────────────────────────────
C-a C-a (other) Toggle to the window
displayed previ-
ously. Note that
this binding de-
faults to the com-
mand character typed
twice, unless over-
ridden. For in-
stance, if you use
the option -e]x,
this command becomes
]].
──────────────────────────────────────────────────────────
C-a a (meta) Send the command
character (C-a) to
window. See escape
command.
──────────────────────────────────────────────────────────
C-a A (title) Allow the user to
enter a name for the
current window.
──────────────────────────────────────────────────────────
C-a b, (break) Send a break to win-
C-a C-b dow.
──────────────────────────────────────────────────────────
C-a B (pow_break) Reopen the terminal
line and send a
break.
──────────────────────────────────────────────────────────
C-a c, (screen) Create a new window
C-a C-c with a shell and
switch to that win-
dow.
──────────────────────────────────────────────────────────
C-a C (clear) Clear the screen.
──────────────────────────────────────────────────────────
C-a d, (detach) Detach screen from
C-a C-d this terminal.
──────────────────────────────────────────────────────────
C-a D D (pow_detach) Detach and logout.
──────────────────────────────────────────────────────────
C-a f, (flow) Toggle flow on, off
C-a C-f or auto.
──────────────────────────────────────────────────────────
C-a F (fit) Resize the window to
the current region
size.
──────────────────────────────────────────────────────────
C-a C-g (vbell) Toggles screen's vi-
sual bell mode.
──────────────────────────────────────────────────────────
C-a h (hardcopy) Write a hardcopy of
the current window
to the file hard-
copy.n.
──────────────────────────────────────────────────────────
C-a H (log) Begins/ends logging
of the current win-
dow to the file
screenlog.n.
──────────────────────────────────────────────────────────
C-a i, (info) Show info about this
C-a C-i window.
──────────────────────────────────────────────────────────
C-a k, (kill) Destroy current win-
C-a C-k dow.
──────────────────────────────────────────────────────────
C-a l, (redisplay) Fully refresh cur-
C-a C-l rent window.
──────────────────────────────────────────────────────────
C-a L (login) Toggle this windows
login slot. Avail-
able only if screen
is configured to up-
date the utmp data-
base.
──────────────────────────────────────────────────────────
C-a m, (lastmsg) Repeat the last mes-
C-a C-m sage displayed in
the message line.
──────────────────────────────────────────────────────────
C-a M (monitor) Toggles monitoring
of the current win-
dow.
──────────────────────────────────────────────────────────
C-a space, (next) Switch to the next
C-a n, window.
C-a C-n
──────────────────────────────────────────────────────────
C-a N (number) Show the number (and
title) of the cur-
rent window.
──────────────────────────────────────────────────────────
C-a backspace, (prev) Switch to the previ-
C-a C-h, ous window (opposite
C-a p, of C-a n).
C-a C-p
──────────────────────────────────────────────────────────
C-a q, (xon) Send a control-q to
C-a C-q the current window.
──────────────────────────────────────────────────────────
C-a Q (only) Delete all regions
but the current one.
See also split, re-
move, focus.
──────────────────────────────────────────────────────────
C-a r, (wrap) Toggle the current
C-a C-r window's line-wrap
setting (turn the
current window's au-
tomatic margins on
and off).
──────────────────────────────────────────────────────────
C-a s, (xoff) Send a control-s to
C-a C-s; the current window.
──────────────────────────────────────────────────────────
C-a S (split) Split the current
region horizontally
into two new ones.
See also only, re-
move, focus.
──────────────────────────────────────────────────────────
C-a t, (time) Show system informa-
C-a C-t tion.
──────────────────────────────────────────────────────────
C-a v (version) Display the version
and compilation
date.
──────────────────────────────────────────────────────────
C-a C-v (digraph) Enter digraph.
C-a w, (windows) Show a list of win-
C-a C-w dow.
──────────────────────────────────────────────────────────
C-a W (width) Toggle 80/132
columns.
──────────────────────────────────────────────────────────
C-a x or C-a C-x (lockscreen) Lock this terminal.
──────────────────────────────────────────────────────────
C-a X (remove) Kill the current re-
gion. See also
split, only, focus.
──────────────────────────────────────────────────────────
C-a z, (suspend) Suspend screen.
C-a C-z Your system must
support BSD-style
job-control.
──────────────────────────────────────────────────────────
C-a Z (reset) Reset the virtual
terminal to its
power-on values.
──────────────────────────────────────────────────────────
C-a . (dumptermcap) Write out a .termcap
file.
──────────────────────────────────────────────────────────
C-a ? (help) Show key bindings.
──────────────────────────────────────────────────────────
C-a \ (quit) Kill all windows and
terminate screen.
──────────────────────────────────────────────────────────
C-a : (colon) Enter command line
mode.
──────────────────────────────────────────────────────────
C-a [, (copy) Enter copy/scroll-
C-a C-[, back mode.
C-a esc
──────────────────────────────────────────────────────────
C-a C-], (paste .) Write the contents
C-a ] of the paste buffer
to the stdin queue
of the current win-
dow.
──────────────────────────────────────────────────────────
C-a {, (history) Copy and paste a
C-a } previous (command)
line.
──────────────────────────────────────────────────────────
C-a > (writebuf) Write paste buffer
to a file.
──────────────────────────────────────────────────────────
C-a < (readbuf) Reads the screen-ex-
change file into the
paste buffer.
──────────────────────────────────────────────────────────
C-a = (removebuf) Removes the file
used by C-a < and C-
a >.
──────────────────────────────────────────────────────────
C-a , (license) Shows where screen
comes from, where it
went to and why you
can use it.
──────────────────────────────────────────────────────────
C-a _ (silence) Start/stop monitor-
ing the current win-
dow for inactivity.
──────────────────────────────────────────────────────────
C-a | (split -v) Split the current
region vertically
into two new ones.
──────────────────────────────────────────────────────────
C-a * (displays) Show a listing of
all currently at-
tached displays.
──────────────────────────────────────────────────────────
CUSTOMIZATION
The socket directory defaults either to $HOME/.screen or simply to
/tmp/screens or preferably to /run/screen chosen at compile-time. If
screen is installed setuid-root, then the administrator should compile
screen with an adequate (not NFS mounted) socket directory. If screen is
not running setuid-root, the user can specify any mode 700 directory in
the environment variable $SCREENDIR.
When screen is invoked, it executes initialization commands from the
files /etc/screenrc and defaults that can be overridden in the following
ways: for the global screenrc file screen searches for the environment
variable $SYSSCREENRC (this override feature may be disabled at compile-
time). The user specific screenrc file is searched in $SCREENRC, then
$HOME/.screenrc. The command line option -c takes precedence over the
above user screenrc files.
Commands in these files are used to set options, bind functions to keys,
and to automatically establish one or more windows at the beginning of
your screen session. Commands are listed one per line, with empty lines
being ignored. A command's arguments are separated by tabs or spaces,
and may be surrounded by single or double quotes. A `#' turns the rest
of the line into a comment, except in quotes. Unintelligible lines are
warned about and ignored. Commands may contain references to environ-
ment variables. The syntax is the shell-like "$VAR " or "${VAR}". Note
that this causes incompatibility with previous screen versions, as now
the '$'-character has to be protected with '\' if no variable substitu-
tion shall be performed. A string in single-quotes is also protected
from variable substitution.
Two configuration files are shipped as examples with your screen distri-
bution: etc/screenrc and etc/etcscreenrc. They contain a number of use-
ful examples for various commands.
Customization can also be done 'on-line'. To enter the command mode type
`C-a :'. Note that commands starting with def change default values,
while others change current settings.
The following commands are available:
acladd usernames [crypted-pw]
addacl usernames
Enable users to fully access this screen session. Usernames can be one
user or a comma separated list of users. This command enables to attach
to the screen session and performs the equivalent of `aclchg usernames
+rwx "#?"'. executed. To add a user with restricted access, use the
`aclchg' command below. If an optional second parameter is supplied, it
should be a crypted password for the named user(s). `Addacl' is a syn-
onym to `acladd'. Multi user mode only.
aclchg usernames permbits list
chacl usernames permbits list
Change permissions for a comma separated list of users. Permission bits
are represented as `r', `w' and `x'. Prefixing `+' grants the permis-
sion, `-' removes it. The third parameter is a comma separated list of
commands and/or windows (specified either by number or title). The spe-
cial list `#' refers to all windows, `?' to all commands. if usernames
consists of a single `*', all known users are affected.
A command can be executed when the user has the `x' bit for it. The
user can type input to a window when he has its `w' bit set and no other
user obtains a writelock for this window. Other bits are currently ig-
nored. To withdraw the writelock from another user in window 2: `aclchg
username -w+w 2'. To allow read-only access to the session: `aclchg
username -w "#"'. As soon as a user's name is known to screen he can at-
tach to the session and (per default) has full permissions for all com-
mand and windows. Execution permission for the acl commands, `at' and
others should also be removed or the user may be able to regain write
permission. Rights of the special username nobody cannot be changed
(see the su command). `Chacl' is a synonym to `aclchg'. Multi user
mode only.
acldel username
Remove a user from screen's access control list. If currently attached,
all the user's displays are detached from the session. He cannot attach
again. Multi user mode only.
aclgrp username [groupname]
Creates groups of users that share common access rights. The name of the
group is the username of the group leader. Each member of the group in-
herits the permissions that are granted to the group leader. That means,
if a user fails an access check, another check is made for the group
leader. A user is removed from all groups the special value none is
used for groupname. If the second parameter is omitted all groups the
user is in are listed.
aclumask [[ users ] +bits | [ users ] -bits... ]
umask [[ users ] +bits | [ users ] -bits... ]
This specifies the access other users have to windows that will be cre-
ated by the caller of the command. Users may be no, one or a comma sep-
arated list of known usernames. If no users are specified, a list of all
currently known users is assumed. Bits is any combination of access
control bits allowed defined with the aclchg command. The special user-
name ? predefines the access that not yet known users will be granted to
any window initially. The special username ?? predefines the access
that not yet known users are granted to any command. Rights of the spe-
cial username nobody cannot be changed (see the su command). `Umask' is
a synonym to `aclumask'.
activity message
When any activity occurs in a background window that is being monitored,
screen displays a notification in the message line. The notification
message can be re-defined by means of the activity command. Each occur-
rence of `%' in message is replaced by the number of the window in which
activity has occurred, and each occurrence of `^G' is replaced by the
definition for bell in your termcap (usually an audible bell). The de-
fault message is
'Activity in window %n'
Note that monitoring is off for all windows by default, but can be al-
tered by use of the monitor command (C-a M).
allpartial [ on | off ]
If set to on, only the current cursor line is refreshed on window
change. This affects all windows and is useful for slow terminal lines.
The previous setting of full/partial refresh for each window is restored
with allpartial off. This is a global flag that immediately takes ef-
fect on all windows overriding the partial settings. It does not change
the default redraw behavior of newly created windows.
altscreen [ on | off ]
If set to on, "alternate screen" support is enabled in virtual termi-
nals, just like in xterm. Initial setting is `off'.
at [identifier][#|*|%] command [args ... ]
Execute a command at other displays or windows as if it had been entered
there. At changes the context (the `current window' or `current dis-
play' setting) of the command. If the first parameter describes a non-
unique context, the command will be executed multiple times. If the
first parameter is of the form `identifier*' then identifier is matched
against user names. The command is executed once for each display of
the selected user(s). If the first parameter is of the form `identi-
fier%' identifier is matched against displays. Displays are named after
the ttys they attach. The prefix `/dev/' or `/dev/tty' may be omitted
from the identifier. If identifier has a `#' or nothing appended it is
matched against window numbers and titles. Omitting an identifier in
front of the `#', `*' or `%'-character selects all users, displays or
windows because a prefix-match is performed. Note that on the affected
display(s) a short message will describe what happened. Permission is
checked for initiator of the at command, not for the owners of the af-
fected display(s). Note that the '#' character works as a comment in-
troducer when it is preceded by whitespace. This can be escaped by pre-
fixing a '\'. Permission is checked for the initiator of the at com-
mand, not for the owners of the affected display(s).
Caveat: When matching against windows, the command is executed at least
once per window. Commands that change the internal arrangement of win-
dows (like other) may be called again. In shared windows the command
will be repeated for each attached display. Beware, when issuing toggle
commands like login! Some commands (e.g. process) require that a dis-
play is associated with the target windows. These commands may not work
correctly under at looping over windows.
attrcolor attrib [attribute/color-modifier]
This command can be used to highlight attributes by changing the color
of the text. If the attribute attrib is in use, the specified at-
tribute/color modifier is also applied. If no modifier is given, the
current one is deleted. See the STRING ESCAPES chapter for the syntax of
the modifier. Screen understands two pseudo-attributes, i stands for
high-intensity foreground color and I for high-intensity background
color.
Examples:
attrcolor b "R"
Change the color to bright red if bold text is to be printed.
attrcolor u "-u b"
Use blue text instead of underline.
attrcolor b ".I"
Use bright colors for bold text. Most terminal emulators do this al-
ready.
attrcolor i "+b"
Make bright colored text also bold.
autodetach [ on | off ]
Sets whether screen will automatically detach upon hangup, which saves
all your running programs until they are resumed with a screen -r com-
mand. When turned off, a hangup signal will terminate screen and all
the processes it contains. Autodetach is on by default.
autonuke [ on | off ]
Sets whether a clear screen sequence should nuke all the output that has
not been written to the terminal. See also obuflimit.
backtick id lifespan autorefresh cmd args...
backtick id
Program the backtick command with the numerical id id. The output of
such a command is used for substitution of the %` string escape. The
specified lifespan is the number of seconds the output is considered
valid. After this time, the command is run again if a corresponding
string escape is encountered. The autorefresh parameter triggers an au-
tomatic refresh for caption and hardstatus strings after the specified
number of seconds. Only the last line of output is used for substitu-
tion.
If both the lifespan and the autorefresh parameters are zero, the back-
tick program is expected to stay in the background and generate output
once in a while. In this case, the command is executed right away and
screen stores the last line of output. If a new line gets printed screen
will automatically refresh the hardstatus or the captions.
The second form of the command deletes the backtick command with the nu-
merical id id.
bce [ on | off ]
Change background-color-erase setting. If bce is set to on, all charac-
ters cleared by an erase/insert/scroll/clear operation will be displayed
in the current background color. Otherwise the default background color
is used.
bell_msg [message]
When a bell character is sent to a background window, screen displays a
notification in the message line. The notification message can be re-
defined by this command. Each occurrence of `%' in message is replaced
by the number of the window to which a bell has been sent, and each oc-
currence of `^G' is replaced by the definition for bell in your termcap
(usually an audible bell). The default message is
'Bell in window %n'
An empty message can be supplied to the bell_msg command to suppress
output of a message line (bell_msg ""). Without parameter, the current
message is shown.
bind [class] key [command [args]]
Bind a command to a key. By default, most of the commands provided by
screen are bound to one or more keys as indicated in the DEFAULT KEY
BINDINGS section, e.g. the command to create a new window is bound to C-
c and c. The bind command can be used to redefine the key bindings and
to define new bindings. The key argument is either a single character,
a two-character sequence of the form ^x (meaning C-x), a backslash fol-
lowed by an octal number (specifying the ASCII code of the character),
or a backslash followed by a second character, such as \^ or \\. The
argument can also be quoted, if you like. If no further argument is
given, any previously established binding for this key is removed. The
command argument can be any command listed in this section.
If a command class is specified via the -c option, the key is bound for
the specified class. Use the command command to activate a class. Com-
mand classes can be used to create multiple command keys or multi-char-
acter bindings.
Some examples:
bind ' ' windows
bind ^k
bind k
bind K kill
bind ^f screen telnet foobar
bind \033 screen -ln -t root -h 1000 9 su
would bind the space key to the command that displays a list of windows
(so that the command usually invoked by C-a C-w would also be available
as C-a space). The next three lines remove the default kill binding from
C-a C-k and C-a k. C-a K is then bound to the kill command. Then it
binds C-f to the command create a window with a TELNET connection to
foobar, and bind escape to the command that creates an non-login window
with a.k.a. root in slot #9, with a superuser shell and a scrollback
buffer of 1000 lines.
bind -c demo1 0 select 10
bind -c demo1 1 select 11
bind -c demo1 2 select 12
bindkey "^B" command -c demo1
makes C-b 0 select window 10, C-b 1 window 11, etc.
bind -c demo2 0 select 10
bind -c demo2 1 select 11
bind -c demo2 2 select 12
bind - command -c demo2
makes C-a - 0 select window 10, C-a - 1 window 11, etc.
bindkey [-d] [-m] [-a] [[-k|-t] string [cmd-args]]
This command manages screen's input translation tables. Every entry in
one of the tables tells screen how to react if a certain sequence of
characters is encountered. There are three tables: one that should con-
tain actions programmed by the user, one for the default actions used
for terminal emulation and one for screen's copy mode to do cursor move-
ment. See section INPUT TRANSLATION for a list of default key bindings.
If the -d option is given, bindkey modifies the default table, -m
changes the copy mode table and with neither option the user table is
selected. The argument string is the sequence of characters to which an
action is bound. This can either be a fixed string or a termcap keyboard
capability name (selectable with the -k option).
Some keys on a VT100 terminal can send a different string if application
mode is turned on (e.g the cursor keys). Such keys have two entries in
the translation table. You can select the application mode entry by
specifying the -a option.
The -t option tells screen not to do inter-character timing. One cannot
turn off the timing if a termcap capability is used.
Cmd can be any of screen's commands with an arbitrary number of args.
If cmd is omitted the key-binding is removed from the table.
Here are some examples of keyboard bindings:
bindkey -d
Show all of the default key bindings. The application mode entries are
marked with [A].
bindkey -k k1 select 1
Make the "F1" key switch to window one.
bindkey -t foo stuff barfoo
Make "foo" an abbreviation of the word "barfoo". Timeout is disabled so
that users can type slowly.
bindkey "\024" mapdefault
This key-binding makes ^T an escape character for key-bindings. If you
did the above stuff barfoo binding, you can enter the word foo by typing
^Tfoo. If you want to insert a ^T you have to press the key twice (i.e.,
escape the escape binding).
bindkey -k F1 command
Make the F11 (not F1!) key an alternative screen escape (besides ^A).
break [duration]
Send a break signal for duration*0.25 seconds to this window. For non-
Posix systems the time interval may be rounded up to full seconds. Most
useful if a character device is attached to the window rather than a
shell process (See also chapter WINDOW TYPES). The maximum duration of a
break signal is limited to 15 seconds.
blanker
Activate the screen blanker. First the screen is cleared. If no blanker
program is defined, the cursor is turned off, otherwise, the program is
started and it's output is written to the screen. The screen blanker is
killed with the first keypress, the read key is discarded.
This command is normally used together with the idle command.
blankerprg [program-args]
Defines a blanker program. Disables the blanker program if an empty ar-
gument is given. Shows the currently set blanker program if no arguments
are given.
breaktype [tcsendbreak|TIOCSBRK|TCSBRK]
Choose one of the available methods of generating a break signal for
terminal devices. This command should affect the current window only.
But it still behaves identical to defbreaktype. This will be changed in
the future. Calling breaktype with no parameter displays the break
method for the current window.
bufferfile [exchange-file]
Change the filename used for reading and writing with the paste buffer.
If the optional argument to the bufferfile command is omitted, the de-
fault setting (/tmp/screen-exchange) is reactivated. The following ex-
ample will paste the system's password file into the screen window (us-
ing the paste buffer, where a copy remains):
C-a : bufferfile /etc/passwd
C-a < C-a ]
C-a : bufferfile
bumpleft
Swaps window with previous one on window list.
bumpright
Swaps window with next one on window list.
c1 [ on | off ]
Change c1 code processing. C1 on tells screen to treat the input charac-
ters between 128 and 159 as control functions. Such an 8-bit code is
normally the same as ESC followed by the corresponding 7-bit code. The
default setting is to process c1 codes and can be changed with the defc1
command. Users with fonts that have usable characters in the c1 posi-
tions may want to turn this off.
caption [ top | bottom ] always|splitonly[string]
caption string [string]
This command controls the display of the window captions. Normally a
caption is only used if more than one window is shown on the display
(split screen mode). But if the type is set to always screen shows a
caption even if only one window is displayed. The default is splitonly.
The second form changes the text used for the caption. You can use all
escapes from the STRING ESCAPES chapter. Screen uses a default of `%3n
%t'.
You can mix both forms by providing a string as an additional argument.
You can have the caption displayed either at the top or bottom of the
window. The default is bottom.
charset set
Change the current character set slot designation and charset mapping.
The first four character of set are treated as charset designators while
the fifth and sixth character must be in range '0' to '3' and set the
GL/GR charset mapping. On every position a '.' may be used to indicate
that the corresponding charset/mapping should not be changed (set is
padded to six characters internally by appending '.' chars). New win-
dows have "BBBB02" as default charset, unless a encoding command is ac-
tive.
The current setting can be viewed with the info command.
chdir [directory]
Change the current directory of screen to the specified directory or, if
called without an argument, to your home directory (the value of the en-
vironment variable $HOME). All windows that are created by means of the
screen command from within .screenrc or by means of C-a : screen ... or
C-a c use this as their default directory. Without a chdir command,
this would be the directory from which screen was invoked.
Hardcopy and log files are always written to the window's default direc-
tory, not the current directory of the process running in the window.
You can use this command multiple times in your .screenrc to start vari-
ous windows in different default directories, but the last chdir value
will affect all the windows you create interactively.
cjkwidth [ on | off ]
Treat ambiguous width characters as full/half width.
clear
Clears the current window and saves its image to the scrollback buffer.
collapse
Reorders window on window list, removing number gaps between them.
colon [prefix]
Allows you to enter .screenrc command lines. Useful for on-the-fly modi-
fication of key bindings, specific window creation and changing set-
tings. Note that the set keyword no longer exists! Usually commands af-
fect the current window rather than default settings for future windows.
Change defaults with commands starting with 'def...'.
If you consider this as the `Ex command mode' of screen, you may regard
C-a esc (copy mode) as its `Vi command mode'.
command [ -c class"]"
This command has the same effect as typing the screen escape character
(^A). It is probably only useful for key bindings. If the -c option is
given, select the specified command class. See also bind and bindkey.
compacthist [ on | off ]
This tells screen whether to suppress trailing blank lines when
scrolling up text into the history buffer.
console [ on | off ]
Grabs or un-grabs the machines console output to a window. Note: Only
the owner of /dev/console can grab the console output. This command is
only available if the machine supports the ioctl TIOCCONS.
copy
Enter copy/scrollback mode. This allows you to copy text from the cur-
rent window and its history into the paste buffer. In this mode a vi-
like `full screen editor' is active:
The editor's movement keys are:
────────────────────────────────────────────────────────────────
h, C-h, move the cursor left.
left arrow
────────────────────────────────────────────────────────────────
j, C-n, move the cursor down.
down arrow
────────────────────────────────────────────────────────────────
k, C-p, move the cursor up.
up arrow
────────────────────────────────────────────────────────────────
l ('el'), move the cursor right.
right arrow
────────────────────────────────────────────────────────────────
0 (zero) C-a move to the leftmost column.
────────────────────────────────────────────────────────────────
+ and - positions one line up and down.
────────────────────────────────────────────────────────────────
H, M and L move the cursor to the leftmost column of the
top, center or bottom line of the window.
────────────────────────────────────────────────────────────────
| moves to the specified absolute column.
────────────────────────────────────────────────────────────────
g or home moves to the beginning of the buffer.
────────────────────────────────────────────────────────────────
G or end moves to the specified absolute line (default:
end of buffer).
────────────────────────────────────────────────────────────────
% jumps to the specified percentage of the buffer.
────────────────────────────────────────────────────────────────
^ or $ move to the leftmost column, to the first or
last non-whitespace character on the line.
────────────────────────────────────────────────────────────────
w, b, and e move the cursor word by word.
────────────────────────────────────────────────────────────────
B, E move the cursor WORD by WORD (as in vi).
────────────────────────────────────────────────────────────────
f/F, t/T move the cursor forward/backward to the next oc-
currence of the target. (eg, '3fy' will move the
cursor to the 3rd 'y' to the right.)
────────────────────────────────────────────────────────────────
; and , Repeat the last f/F/t/T command in the same/op-
posite direction.
────────────────────────────────────────────────────────────────
C-e and C-y scroll the display up/down by one line while
preserving the cursor position.
────────────────────────────────────────────────────────────────
C-u and C-d scroll the display up/down by the specified
amount of lines while preserving the cursor po-
sition. (Default: half screen-full).
────────────────────────────────────────────────────────────────
C-b and C-f scroll the display up/down a full screen.
────────────────────────────────────────────────────────────────
Note: Emacs style movement keys can be customized by a .screenrc com-
mand. (E.g. markkeys "h=^B:l=^F:$=^E") There is no simple method for a
full emacs-style keymap, as this involves multi-character codes.
Some keys are defined to do mark and replace operations.
The copy range is specified by setting two marks. The text between these
marks will be highlighted. Press:
space or enter to set the first or second mark respectively. If
mousetrack is set to `on', marks can also be set using left mouse
click.
Y and y used to mark one whole line or to mark from start of
line.
W marks exactly one word.
Any of these commands can be prefixed with a repeat count number by
pressing digits
0..9 which is taken as a repeat count.
Example: C-a C-[ H 10 j 5 Y will copy lines 11 to 15 into the paste
buffer.
The following search keys are defined:
/ Vi-like search forward.
? Vi-like search backward.
C-a s Emacs style incremental search forward.
C-r Emacs style reverse i-search.
n Find next search pattern.
N Find previous search pattern.
There are however some keys that act differently than in vi. Vi does
not allow one to yank rectangular blocks of text, but screen does.
Press: c or C to set the left or right margin respectively. If no repeat
count is given, both default to the current cursor position.
Example: Try this on a rather full text screen:
C-a [ M 20 l SPACE c 10 l 5 j C SPACE.
This moves one to the middle line of the screen, moves in 20 columns
left, marks the beginning of the paste buffer, sets the left column,
moves 5 columns down, sets the right column, and then marks the end of
the paste buffer. Now try:
C-a [ M 20 l SPACE 10 l 5 j SPACE
and notice the difference in the amount of text copied.
J joins lines. It toggles between 4 modes: lines separated by a newline
character (012), lines glued seamless, lines separated by a single
whitespace and comma separated lines. Note that you can prepend the new-
line character with a carriage return character, by issuing a crlf on.
v or V is for all the vi users with :set numbers - it toggles the left
margin between column 9 and 1. Press
a before the final space key to toggle in append mode. Thus the contents
of the paste buffer will not be overwritten, but is appended to.
A toggles in append mode and sets a (second) mark.
> sets the (second) mark and writes the contents of the paste buffer to
the screen-exchange file (/tmp/screen-exchange per default) once copy-
mode is finished.
This example demonstrates how to dump the whole scrollback buffer to
that file: C-A [ g SPACE G $ >.
C-g gives information about the current line and column.
x or o exchanges the first mark and the current cursor position. You can
use this to adjust an already placed mark.
C-l ('el') will redraw the screen.
@ does nothing. Does not even exit copy mode.
All keys not described here exit copy mode.
copy_reg [key]
No longer exists, use readreg instead.
crlf [ on | off ]
This affects the copying of text regions with the `C-a [' command. If it
is set to `on', lines will be separated by the two character sequence
`CR' - `LF'. Otherwise (default) only `LF' is used. When no parameter
is given, the state is toggled.
debug [ on | off ]
Turns runtime debugging on or off. If screen has been compiled with op-
tion -DDEBUG debugging available and is turned on per default. Note that
this command only affects debugging output from the main SCREEN process
correctly. Debug output from attacher processes can only be turned off
once and forever.
defc1 [ on | off ]
Same as the c1 command except that the default setting for new windows
is changed. Initial setting is `on'.
defautonuke [ on | off ]
Same as the autonuke command except that the default setting for new
displays is changed. Initial setting is `off'. Note that you can use
the special `AN' terminal capability if you want to have a dependency on
the terminal type.
defbce [ on | off ]
Same as the bce command except that the default setting for new windows
is changed. Initial setting is `off'.
defbreaktype [tcsendbreak|TIOCSBRK|TCSBRK]
Choose one of the available methods of generating a break signal for
terminal devices. The preferred methods are tcsendbreak and TIOCSBRK.
The third, TCSBRK, blocks the complete screen session for the duration
of the break, but it may be the only way to generate long breaks. Tc-
sendbreak and TIOCSBRK may or may not produce long breaks with spikes
(e.g. 4 per second). This is not only system-dependent, this also dif-
fers between serial board drivers. Calling defbreaktype with no parame-
ter displays the current setting.
defcharset [set]
Like the charset command except that the default setting for new windows
is changed. Shows current default if called without argument.
defdynamictitle [ on | off ]
Set default behaviour for new windows regarding if screen should change
window title when seeing proper escape sequence. See also "TITLES (nam-
ing windows)" section.
defescape xy
Set the default command characters. This is equivalent to the escape ex-
cept that it is useful multiuser sessions only. In a multiuser session
escape changes the command character of the calling user, where de-
fescape changes the default command characters for users that will be
added later.
defflow [ on | off | auto [ interrupt ]]
Same as the flow command except that the default setting for new windows
is changed. Initial setting is `auto'. Specifying defflow auto inter-
rupt is the same as the command-line options -fa and -i.
defgr [ on | off ]
Same as the gr command except that the default setting for new windows
is changed. Initial setting is `off'.
defhstatus [status]
The hardstatus line that all new windows will get is set to status.
This command is useful to make the hardstatus of every window display
the window number or title or the like. Status may contain the same di-
rectives as in the window messages, but the directive escape character
is '^E' (octal 005) instead of '%'. This was done to make a misinter-
pretation of program generated hardstatus lines impossible. If the pa-
rameter status is omitted, the current default string is displayed. Per
default the hardstatus line of new windows is empty.
defencoding enc
Same as the encoding command except that the default setting for new
windows is changed. Initial setting is the encoding taken from the ter-
minal.
deflog [ on | off ]
Same as the log command except that the default setting for new windows
is changed. Initial setting is `off'.
deflogin [ on | off ]
Same as the login command except that the default setting for new win-
dows is changed. This is initialized with `on' as distributed (see con-
fig.h.in).
defmode mode
The mode of each newly allocated pseudo-tty is set to mode. Mode is an
octal number. When no defmode command is given, mode 0622 is used.
defmonitor [ on | off]
Same as the monitor command except that the default setting for new win-
dows is changed. Initial setting is `off'.
defmousetrack [ on | off ]
Same as the mousetrack command except that the default setting for new
windows is changed. Initial setting is `off'.
defnonblock [ on | off | numsecs]
Same as the nonblock command except that the default setting for dis-
plays is changed. Initial setting is `off'.
defobuflimit limit
Same as the obuflimit command except that the default setting for new
displays is changed. Initial setting is 256 bytes. Note that you can
use the special 'OL' terminal capability if you want to have a depen-
dency on the terminal type.
defscrollback num
Same as the scrollback command except that the default setting for new
windows is changed. Initial setting is 100.
defshell command
Synonym to the shell .screenrc command. See there.
defsilence [ on | off ]
Same as the silence command except that the default setting for new win-
dows is changed. Initial setting is `off'.
defslowpaste msec
Same as the slowpaste command except that the default setting for new
windows is changed. Initial setting is 0 milliseconds, meaning `off'.
defutf8 [ on | off ]
Same as the utf8 command except that the default setting for new windows
is changed. Initial setting is `on' if screen was started with -U, oth-
erwise `off'.
defwrap [ on | off ]
Same as the wrap command except that the default setting for new windows
is changed. Initially line-wrap is on and can be toggled with the wrap
command (C-a r) or by means of "C-a : wrap on|off".
defwritelock [ on | off | auto ]
Same as the writelock command except that the default setting for new
windows is changed. Initially writelocks will off.
detach [-h]
Detach the screen session (disconnect it from the terminal and put it
into the background). This returns you to the shell where you invoked
screen. A detached screen can be resumed by invoking screen with the -r
option (see also section COMMAND-LINE OPTIONS). The -h option tells
screen to immediately close the connection to the terminal (hangup).
dinfo
Show what screen thinks about your terminal. Useful if you want to know
why features like color or the alternate charset don't work.
displays
Shows a tabular listing of all currently connected user front-ends (dis-
plays). This is most useful for multiuser sessions. The following keys
can be used in displays list:
───────────────────────────────────────────────────────
k, C-p, or up Move up one line.
───────────────────────────────────────────────────────
j, C-n, or down Move down one line.
───────────────────────────────────────────────────────
C-a or home Move to the first line.
───────────────────────────────────────────────────────
C-e or end Move to the last line.
───────────────────────────────────────────────────────
C-u or C-d Move one half page up or down.
───────────────────────────────────────────────────────
C-b or C-f Move one full page up or down.
───────────────────────────────────────────────────────
mouseclick Move to the selected line.
Available when mousetrack is
set to on.
───────────────────────────────────────────────────────
space Refresh the list
───────────────────────────────────────────────────────
d Detach that display
───────────────────────────────────────────────────────
D Power detach that display
───────────────────────────────────────────────────────
C-g, enter, or escape Exit the list
───────────────────────────────────────────────────────
The following is an example of what displays could look like:
xterm 80x42 jnweiger@/dev/ttyp4 0(m11) &rWx
facit 80x24 mlschroe@/dev/ttyhf nb 11(tcsh) rwx
xterm 80x42 jnhollma@/dev/ttyp5 0(m11) &R.x
(A) (B) (C) (D) (E) (F)(G) (H)(I)
The legend is as follows:
(A) The terminal type known by screen for this display.
(B) Displays geometry as width x height.
(C) Username who is logged in at the display.
(D) Device name of the display or the attached device
(E) Display is in blocking or nonblocking mode. The available
modes are "nb", "NB", "Z<", "Z>", and "BL".
(F) Number of the window
(G) Name/title of window
(H) Whether the window is shared
(I) Window permissions. Made up of three characters.
┌─────────────────────────────────────────────────────────┐
│ Window permissions indicators │
├──────────────────┬──────────────────┬───────────────────┤
│ 1st character │ 2nd character │ 3rd character │
├─────┬────────────┼─────┬────────────┼─────┬─────────────┤
│ - │no read │ - │no write │ - │no execute │
├─────┼────────────┼─────┼────────────┼─────┼─────────────┤
│ r │read │ w │write │ x │execute │
├─────┼────────────┼─────┼────────────┼─────┼─────────────┤
│ │ │ W │own wlock │ │ │
├─────┴────────────┴─────┴────────────┴─────┴─────────────┤
│ Indicators of permissions suppressed by a foreign wlock │
├─────┬────────────┬─────┬────────────┬─────┬─────────────┤
│ R │read only │ . │no write │ │ │
└─────┴────────────┴─────┴────────────┴─────┴─────────────┘
displays needs a region size of at least 10 characters wide and 5
characters high in order to display.
digraph [preset[unicode-value]]
This command prompts the user for a digraph sequence. The next two char-
acters typed are looked up in a builtin table and the resulting charac-
ter is inserted in the input stream. For example, if the user enters
'a"', an a-umlaut will be inserted. If the first character entered is a
0 (zero), screen will treat the following characters (up to three) as an
octal number instead. The optional argument preset is treated as user
input, thus one can create an umlaut key. For example the command
"bindkey ^K digraph '"'" enables the user to generate an a-umlaut by
typing CTRL-K a. When a non-zero unicode-value is specified, a new di-
graph is created with the specified preset. The digraph is unset if a
zero value is provided for the unicode-value.
dumptermcap
Write the termcap entry for the virtual terminal optimized for the cur-
rently active window to the file .termcap in the user's $HOME/.screen
directory (or wherever screen stores its sockets. See the FILES section
below). This termcap entry is identical to the value of the environment
variable $TERMCAP that is set up by screen for each window. For terminfo
based systems you will need to run a converter like captoinfo and then
compile the entry with tic.
dynamictitle [ on | off ]
Change behaviour for windows regarding if screen should change window
title when seeing proper escape sequence. See also "TITLES (naming win-
dows)" section.
echo [-n] message
The echo command may be used to annoy screen users with a 'message of
the day'. Typically installed in a global /etc/screenrc. The option -n
may be used to suppress the line feed. See also sleep. Echo is also
useful for online checking of environment variables.
encoding enc [enc]
Tell screen how to interpret the input/output. The first argument sets
the encoding of the current window. Each window can emulate a different
encoding. The optional second parameter overwrites the encoding of the
connected terminal. It should never be needed as screen uses the locale
setting to detect the encoding. There is also a way to select a termi-
nal encoding depending on the terminal type by using the KJ termcap en-
try.
Supported encodings are eucJP, SJIS, eucKR, eucCN, Big5, GBK, KOI8-R,
KOI8-U, CP1251, UTF-8, ISO8859-2, ISO8859-3, ISO8859-4, ISO8859-5,
ISO8859-6, ISO8859-7, ISO8859-8, ISO8859-9, ISO8859-10, ISO8859-15, jis.
See also defencoding, which changes the default setting of a new window.
escape xy
Set the command character to x and the character generating a literal
command character (by triggering the meta command) to y (similar to the
-e option). Each argument is either a single character, a two-character
sequence of the form ^x (meaning C-x), a backslash followed by an octal
number (specifying the ASCII code of the character), or a backslash fol-
lowed by a second character, such as \^ or \\. The default is ^Aa.
eval command1[command2 ...]
Parses and executes each argument as separate command.
exec [[fdpat]newcommand [args ...]]
Run a unix subprocess (specified by an executable path newcommand and
its optional arguments) in the current window. The flow of data between
newcommands stdin/stdout/stderr, the process originally started in the
window (let us call it "application-process") and screen itself (window)
is controlled by the file descriptor pattern fdpat. This pattern is ba-
sically a three character sequence representing stdin, stdout and stderr
of newcommand. A dot (.) connects the file descriptor to screen. An ex-
clamation mark (!) causes the file descriptor to be connected to the ap-
plication-process. A colon (:) combines both. User input will go to
newcommand unless newcommand receives the application-process' output
(fdpats first character is `!' or `:') or a pipe symbol (|) is added (as
a fourth character) to the end of fdpat.
Invoking `exec' without arguments shows name and arguments of the cur-
rently running subprocess in this window. Only one subprocess a time can
be running in each window.
When a subprocess is running the `kill' command will affect it instead
of the windows process.
Refer to the postscript file `doc/fdpat.ps' for a confusing illustration
of all 21 possible combinations. Each drawing shows the digits 2,1,0
representing the three file descriptors of newcommand. The box marked
`W' is the usual pty that has the application-process on its slave side.
The box marked `P' is the secondary pty that now has screen at its mas-
ter side.
Abbreviations: Whitespace between the word `exec' and fdpat and the com-
mand can be omitted. Trailing dots and a fdpat consisting only of dots
can be omitted. A simple `|' is synonymous for the pattern `!..|'; the
word exec can be omitted here and can always be replaced by `!'.
Examples:
exec ... /bin/sh
exec /bin/sh
!/bin/sh
Creates another shell in the same window, while the origi-
nal shell is still running. Output of both shells is dis-
played and user input is sent to the new /bin/sh.
exec !.. stty 19200
exec ! stty 19200
!!stty 19200
Set the speed of the window's tty. If your stty command
operates on stdout, then add another `!'.
exec !..| less
|less
This adds a pager to the window output. The special char-
acter `|' is needed to give the user control over the
pager although it gets its input from the window's
process. This works, because less listens on stderr (a be-
havior that screen would not expect without the `|') when
its stdin is not a tty. Less versions newer than 177 fail
miserably here; good old pg still works.
!:sed -n s/.*Error.*/\007/p
Sends window output to both, the user and the sed command.
The sed inserts an additional bell character (oct. 007) to
the window output seen by screen. This will cause "Bell
in window x" messages, whenever the string "Error" appears
in the window.
fit
Change the window size to the size of the current region. This command
is needed because screen doesn't adapt the window size automatically if
the window is displayed more than once.
flow [ on | off | auto]
Sets the flow-control mode for this window. Without parameters it cy-
cles the current window's flow-control setting from "automatic" to "on"
to "off". See the discussion on FLOW-CONTROL later on in this document
for full details and note, that this is subject to change in future re-
leases. Default is set by `defflow'.
focus [ next | prev | up | down | left | right | top | bottom ]
Move the input focus to the next region. This is done in a cyclic way so
that the top left region is selected after the bottom right one. If no
option is given it defaults to `next'. The next region to be selected is
determined by how the regions are layered. Normally, the next region in
the same layer would be selected. However, if that next region contains
one or more layers, the first region in the highest layer is selected
first. If you are at the last region of the current layer, `next' will
move the focus to the next region in the lower layer (if there is a
lower layer). `Prev' cycles in the opposite order. See split for more
information about layers.
The rest of the options (`up', `down', `left', `right', `top', and `bot-
tom') are more indifferent to layers. The option `up' will move the fo-
cus upward to the region that is touching the upper left corner of the
current region. `Down' will move downward to the region that is touch-
ing the lower left corner of the current region. The option `left' will
move the focus leftward to the region that is touching the upper left
corner of the current region, while `right' will move rightward to the
region that is touching the upper right corner of the current region.
Moving left from a left most region or moving right from a right most
region will result in no action.
The option `top' will move the focus to the very first region in the up-
per list corner of the screen, and `bottom' will move to the region in
the bottom right corner of the screen. Moving up from a top most region
or moving down from a bottom most region will result in no action.
Useful bindings are (h, j, k, and l as in vi)
bind h focus left
bind j focus down
bind k focus up
bind l focus right
bind t focus top
bind b focus bottom
Note that k is traditionally bound to the kill command.
focusminsize [ ( width|max|_ ) ( height|max|_ ) ]
This forces any currently selected region to be automatically resized at
least a certain width and height. All other surrounding regions will be
resized in order to accommodate. This constraint follows every time the
focus command is used. The resize command can be used to increase either
dimension of a region, but never below what is set with focusminsize.
The underscore `_' is a synonym for max. Setting a width and height of
`0 0' (zero zero) will undo any constraints and allow for manual resiz-
ing. Without any parameters, the minimum width and height is shown.
gr [ on | off ]
Turn GR charset switching on/off. Whenever screen sees an input charac-
ter with the 8th bit set, it will use the charset stored in the GR slot
and print the character with the 8th bit stripped. The default (see also
defgr) is not to process GR switching because otherwise the ISO88591
charset would not work.
group [grouptitle]
Change or show the group the current window belongs to. Windows can be
moved around between different groups by specifying the name of the des-
tination group. Without specifying a group, the title of the current
group is displayed.
hardcopy [-h] [file]
Writes out the currently displayed image to the file file, or, if no
filename is specified, to hardcopy.n in the default directory, where n
is the number of the current window. This either appends or overwrites
the file if it exists. See below. If the option -h is specified, dump
also the contents of the scrollback buffer.
hardcopy_append [ on | off ]
If set to "on", screen will append to the "hardcopy.n" files created by
the command C-a h, otherwise these files are overwritten each time. De-
fault is `off'.
hardcopydir directory
Defines a directory where hardcopy files will be placed. If unset, hard-
copys are dumped in screen's current working directory.
hardstatus [ on | off ]
hardstatus [ always ] firstline | lastline | message | ignore [ string ]
hardstatus string [ string ]
This command configures the use and emulation of the terminal's hardsta-
tus line. The first form toggles whether screen will use the hardware
status line to display messages. If the flag is set to `off', these mes-
sages are overlaid in reverse video mode at the display line. The de-
fault setting is `on'.
The second form tells screen what to do if the terminal doesn't have a
hardstatus line (i.e. the termcap/terminfo capabilities "hs", "ts", "fs"
and "ds" are not set). When firstline/lastline is used, screen will re-
serve the first/last line of the display for the hardstatus. message
uses screen's message mechanism and ignore tells screen never to display
the hardstatus. If you prepend the word always to the type (e.g., al-
wayslastline), screen will use the type even if the terminal supports a
hardstatus.
The third form specifies the contents of the hardstatus line. '%h' is
used as default string, i.e., the stored hardstatus of the current win-
dow (settable via ESC]0;<string>^G or ESC_<string>ESC\) is displayed.
You can customize this to any string you like including the escapes from
the STRING ESCAPES chapter. If you leave out the argument string, the
current string is displayed.
You can mix the second and third form by providing the string as addi-
tional argument.
height [-w|-d] [lines [cols]]
Set the display height to a specified number of lines. When no argument
is given it toggles between 24 and 42 lines display. You can also spec-
ify a width if you want to change both values. The -w option tells
screen to leave the display size unchanged and just set the window size,
-d vice versa.
help[class]
Not really a online help, but displays a help screen showing you all the
key bindings. The first pages list all the internal commands followed
by their current bindings. Subsequent pages will display the custom
commands, one command per key. Press space when you're done reading
each page, or return to exit early. All other characters are ignored.
If the -c option is given, display all bound commands for the specified
command class. See also DEFAULT KEY BINDINGS section.
history
Usually users work with a shell that allows easy access to previous com-
mands. For example csh has the command !! to repeat the last command
executed. Screen allows you to have a primitive way of re-calling the
command that started ...: You just type the first letter of that com-
mand, then hit `C-a {' and screen tries to find a previous line that
matches with the `prompt character' to the left of the cursor. This line
is pasted into this window's input queue. Thus you have a crude command
history (made up by the visible window and its scrollback buffer).
hstatus status
Change the window's hardstatus line to the string status.
idle [timeout[cmd-args]]
Sets a command that is run after the specified number of seconds inac-
tivity is reached. This command will normally be the blanker command to
create a screen blanker, but it can be any screen command. If no com-
mand is specified, only the timeout is set. A timeout of zero (or the
special timeout off) disables the timer. If no arguments are given, the
current settings are displayed.
ignorecase [ on | off ]
Tell screen to ignore the case of characters in searches. Default is
`off'. Without any options, the state of ignorecase is toggled.
info
Uses the message line to display some information about the current win-
dow: the cursor position in the form (column,row) starting with (1,1),
the terminal width and height plus the size of the scrollback buffer in
lines, like in (80,24)+50, the current state of window XON/XOFF flow
control is shown like this (See also section FLOW CONTROL):
┌──────────┬──────────────────────────────────────────────────────────┐
│ +flow │ automatic flow control, currently on. │
├──────────┼──────────────────────────────────────────────────────────┤
│ -flow │ automatic flow control, currently off. │
├──────────┼──────────────────────────────────────────────────────────┤
│ +(+)flow │ flow control enabled. Agrees with automatic control. │
├──────────┼──────────────────────────────────────────────────────────┤
│ -(+)flow │ flow control disabled. Disagrees with automatic control. │
├──────────┼──────────────────────────────────────────────────────────┤
│ +(-)flow │ flow control enabled. Disagrees with automatic control. │
├──────────┼──────────────────────────────────────────────────────────┤
│ -(-)flow │ flow control disabled. Agrees with automatic control. │
└──────────┴──────────────────────────────────────────────────────────┘
The current line wrap setting (`+wrap' indicates enabled, `-wrap' not)
is also shown. The flags `ins', `org', `app', `log', `mon' or `nored'
are displayed when the window is in insert mode, origin mode, applica-
tion-keypad mode, has output logging, activity monitoring or partial re-
draw enabled.
The currently active character set (G0, G1, G2, or G3) and in square
brackets the terminal character sets that are currently designated as G0
through G3 is shown. If the window is in UTF-8 mode, the string UTF-8 is
shown instead.
Additional modes depending on the type of the window are displayed at
the end of the status line (See also chapter WINDOW TYPES).
If the state machine of the terminal emulator is in a non-default state,
the info line is started with a string identifying the current state.
For system information use the time command.
ins_reg [key]
No longer exists, use paste instead.
kill
Kill current window.
If there is an `exec' command running then it is killed. Otherwise the
process (shell) running in the window receives a HANGUP condition, the
window structure is removed and screen (your display) switches to an-
other window. When the last window is destroyed, screen exits. After a
kill screen switches to the previously displayed window.
Note: Emacs users should keep this command in mind, when killing a line.
It is recommended not to use C-a as the screen escape key or to rebind
kill to C-a K.
lastmsg
Redisplay the last contents of the message/status line. Useful if
you're typing when a message appears, because the message goes away
when you press a key (unless your terminal has a hardware status line).
Refer to the commands msgwait and msgminwait for fine tuning.
layout new [title]
Create a new layout. The screen will change to one whole region and be
switched to the blank window. From here, you build the regions and the
windows they show as you desire. The new layout will be numbered with
the smallest available integer, starting with zero. You can optionally
give a title to your new layout. Otherwise, it will have a default ti-
tle of layout. You can always change the title later by using the com-
mand layout title.
layout remove [n|title]
Remove, or in other words, delete the specified layout. Either the num-
ber or the title can be specified. Without either specification, screen
will remove the current layout.
Removing a layout does not affect your set windows or regions.
layout next
Switch to the next layout available
layout prev
Switch to the previous layout available
layout select [n|title]
Select the desired layout. Either the number or the title can be speci-
fied. Without either specification, screen will prompt and ask which
screen is desired. To see which layouts are available, use the layout
show command.
layout show
List on the message line the number(s) and title(s) of the available
layout(s). The current layout is flagged.
layout title [title]
Change or display the title of the current layout. A string given will
be used to name the layout. Without any options, the current title and
number is displayed on the message line.
layout number [n]
Change or display the number of the current layout. An integer given
will be used to number the layout. Without any options, the current num-
ber and title is displayed on the message line.
layout attach [title|:last]
Change or display which layout to reattach back to. The default is
:last, which tells screen to reattach back to the last used layout just
before detachment. By supplying a title, You can instruct screen to
reattach to a particular layout regardless which one was used at the
time of detachment. Without any options, the layout to reattach to will
be shown in the message line.
layout save [n|title]
Remember the current arrangement of regions. When used, screen will re-
member the arrangement of vertically and horizontally split regions.
This arrangement is restored when a screen session is reattached or
switched back from a different layout. If the session ends or the screen
process dies, the layout arrangements are lost. The layout dump command
should help in this situation. If a number or title is supplied, screen
will remember the arrangement of that particular layout. Without any op-
tions, screen will remember the current layout.
Saving your regions can be done automatically by using the layout au-
tosave command.
layout autosave [ on | off]
Change or display the status of automatically saving layouts. The de-
fault is on, meaning when screen is detached or changed to a different
layout, the arrangement of regions and windows will be remembered at the
time of change and restored upon return. If autosave is set to off,
that arrangement will only be restored to either to the last manual
save, using layout save, or to when the layout was first created, to a
single region with a single window. Without either an on or off, the
current status is displayed on the message line.
layout dump [filename]
Write to a file the order of splits made in the current layout. This is
useful to recreate the order of your regions used in your current lay-
out. Only the current layout is recorded. While the order of the regions
are recorded, the sizes of those regions and which windows correspond to
which regions are not. If no filename is specified, the default is lay-
out-dump, saved in the directory that the screen process was started in.
If the file already exists, layout dump will append to that file. As an
example:
C-a : layout dump /home/user/.screenrc
will save or append the layout to the user's .screenrc file.
license
Display the disclaimer page. This is done whenever screen is started
without options, which should be often enough. See also the startup_mes-
sage command.
lockscreen
Lock this display. Call a screenlock program. Screen does not accept
any command keys until this program terminates. Meanwhile processes in
the windows may continue, as the windows are in the `detached' state.
The screenlock program may be changed through the environment variable
$LOCKPRG (which must be set in the shell from which screen is started)
and is executed with the user's uid and gid.
Warning: When you leave other shells unlocked and you have no password
set on screen, the lock is void: One could easily re-attach from an un-
locked shell. This feature should rather be called `lockterminal'.
log [ on | off ]
Start/stop writing output of the current window to a file screenlog.n in
the window's default directory, where n is the number of the current
window. This filename can be changed with the `logfile' command. If no
parameter is given, the state of logging is toggled. The session log is
appended to the previous contents of the file if it already exists. The
current contents and the contents of the scrollback history are not in-
cluded in the session log. Default is `off'.
logfile filename
logfile flush secs
Defines the name the log files will get. The default is screenlog.%n.
The second form changes the number of seconds screen will wait before
flushing the logfile buffer to the file-system. The default value is 10
seconds.
login [ on | off ]
Adds or removes the entry in the utmp database file for the current win-
dow. This controls if the window is `logged in'. When no parameter is
given, the login state of the window is toggled. Additionally to that
toggle, it is convenient having a `log in' and a `log out' key. E.g.
`bind I login on' and `bind O login off' will map these keys to be C-a I
and C-a O. The default setting (in config.h.in) should be on for a
screen that runs under suid-root. Use the deflogin command to change
the default login state for new windows. Both commands are only present
when screen has been compiled with utmp support.
logtstamp [on|off]
logtstamp after [secs]
logtstamp string
[string]
This command controls logfile time-stamp mechanism of screen. If time-
stamps are turned on, screen adds a string containing the current time
to the logfile after two minutes of inactivity. When output continues
and more than another two minutes have passed, a second time-stamp is
added to document the restart of the output. You can change this timeout
with the second form of the command. The third form is used for cus-
tomizing the time-stamp string (`-- %n:%t -- time-stamp -- %M/%d/%y
%c:%s --\n' by default).
mapdefault
Tell screen that the next input character should only be looked up in
the default bindkey table. See also bindkey.
mapnotnext
Like mapdefault, but don't even look in the default bindkey table.
maptimeout [timeout]
Set the inter-character timer for input sequence detection to a timeout
of timeout ms. The default timeout is 300ms. Maptimeout with no argu-
ments shows the current setting. See also bindkey.
markkeys string
This is a method of changing the keymap used for copy/history mode. The
string is made up of oldchar=newchar pairs which are separated by `:'.
Example: The string B=^B:F=^F will change the keys `C-b' and `C-f' to
the vi style binding (scroll up/down fill page). This happens to be the
default binding for `B' and `F'. The command markkeys h=^B:l=^F:$=^E
would set the mode for an emacs-style binding. If your terminal sends
characters, that cause you to abort copy mode, then this command may
help by binding these characters to do nothing. The no-op character is
`@' and is used like this: markkeys @=L=H if you do not want to use the
`H' or `L' commands any longer. As shown in this example, multiple keys
can be assigned to one function in a single statement.
maxwin num
Set the maximum window number screen will create. Doesn't affect already
existing windows. The number can be increased only when there are no ex-
isting windows.
meta
Insert the command character (C-a) in the current window's input stream.
monitor [ on | off ]
Toggles activity monitoring of windows. When monitoring is turned on
and an affected window is switched into the background, you will receive
the activity notification message in the status line at the first sign
of output and the window will also be marked with an `@' in the window-
status display. Monitoring is initially off for all windows.
mousetrack [ on | off ]
This command determines whether screen will watch for mouse clicks. When
this command is enabled, regions that have been split in various ways
can be selected by pointing to them with a mouse and left-clicking them.
Without specifying on or off, the current state is displayed. The de-
fault state is determined by the defmousetrack command.
msgminwait sec
Defines the time screen delays a new message when one message is cur-
rently displayed. The default is 1 second.
msgwait sec
Defines the time a message is displayed if screen is not disturbed by
other activity. The default is 5 seconds.
multiuser [ on | off ]
Switch between singleuser and multiuser mode. Standard screen operation
is singleuser. In multiuser mode the commands `acladd', `aclchg',
`aclgrp' and `acldel' can be used to enable (and disable) other users
accessing this screen session.
nethack [ on | off ]
Changes the kind of error messages used by screen. When you are famil-
iar with the game nethack, you may enjoy the nethack-style messages
which will often blur the facts a little, but are much funnier to read.
Anyway, standard messages often tend to be unclear as well.
This option is only available if screen was compiled with the NETHACK
flag defined. The default setting is then determined by the presence of
the environment variable $NETHACKOPTIONS and the file ~/.nethackrc - if
either one is present, the default is on.
next
Switch to the next window. This command can be used repeatedly to cycle
through the list of windows.
nonblock [ on | off | numsecs ]
Tell screen how to deal with user interfaces (displays) that cease to
accept output. This can happen if a user presses ^S or a TCP/modem con-
nection gets cut but no hangup is received. If nonblock is off (this is
the default) screen waits until the display restarts to accept the out-
put. If nonblock is on, screen waits until the timeout is reached (on is
treated as 1s). If the display still doesn't receive characters, screen
will consider it blocked and stop sending characters to it. If at some
time it restarts to accept characters, screen will unblock the display
and redisplay the updated window contents.
number [[+|-]n]
Change the current window's number. If the given number n is already
used by another window, both windows exchange their numbers. If no argu-
ment is specified, the current window number (and title) is shown. Using
`+' or `-' will change the window's number by the relative amount speci-
fied.
obuflimit [limit]
If the output buffer contains more bytes than the specified limit, no
more data will be read from the windows. The default value is 256. If
you have a fast display (like xterm), you can set it to some higher
value. If no argument is specified, the current setting is displayed.
only
Kill all regions but the current one.
other
Switch to the window displayed previously. If this window does no longer
exist, other has the same effect as next.
partial [ on | off ]
Defines whether the display should be refreshed (as with redisplay) af-
ter switching to the current window. This command only affects the cur-
rent window. To immediately affect all windows use the allpartial com-
mand. Default is `off', of course. This default is fixed, as there is
currently no defpartial command.
password [crypted_pw]
Present a crypted password in your .screenrc file and screen will ask
for it, whenever someone attempts to resume a detached. This is useful
if you have privileged programs running under screen and you want to
protect your session from reattach attempts by another user masquerading
as your uid (i.e. any superuser.) If no crypted password is specified,
screen prompts twice for typing a password and places its encryption in
the paste buffer. Default is `none', this disables password checking.
paste [registers [dest_reg]]
Write the (concatenated) contents of the specified registers to the
stdin queue of the current window. The register '.' is treated as the
paste buffer. If no parameter is given the user is prompted for a single
register to paste. The paste buffer can be filled with the copy, his-
tory and readbuf commands. Other registers can be filled with the reg-
ister, readreg and paste commands. If paste is called with a second ar-
gument, the contents of the specified registers is pasted into the named
destination register rather than the window. If '.' is used as the sec-
ond argument, the displays paste buffer is the destination. Note, that
paste uses a wide variety of resources: Whenever a second argument is
specified no current window is needed. When the source specification
only contains registers (not the paste buffer) then there need not be a
current display (terminal attached), as the registers are a global re-
source. The paste buffer exists once for every user.
pastefont [ on | off ]
Tell screen to include font information in the paste buffer. The default
is not to do so. This command is especially useful for multi character
fonts like kanji.
pow_break
Reopen the window's terminal line and send a break condition. See
`break'.
pow_detach
Power detach. Mainly the same as detach, but also sends a HANGUP signal
to the parent process of screen. CAUTION: This will result in a logout,
when screen was started from your login-shell.
pow_detach_msg [message]
The message specified here is output whenever a `Power detach' was per-
formed. It may be used as a replacement for a logout message or to reset
baud rate, etc. Without parameter, the current message is shown.
prev
Switch to the window with the next lower number. This command can be
used repeatedly to cycle through the list of windows.
printcmd [cmd]
If cmd is not an empty string, screen will not use the terminal capabil-
ities po/pf if it detects an ansi print sequence ESC [ 5 i, but pipe the
output into cmd. This should normally be a command like lpr or printcmd
without a command displays the current setting. The ansi sequence ESC [
4 i ends printing and closes the pipe.
Warning: Be careful with this command! If other user have write access
to your terminal, they will be able to fire off print commands.
process [key]
Stuff the contents of the specified register into screen's input queue.
If no argument is given you are prompted for a register name. The text
is parsed as if it had been typed in from the user's keyboard. This com-
mand can be used to bind multiple actions to a single key.
quit
Kill all windows and terminate screen. Note that on VT100-style termi-
nals the keys C-4 and C-\ are identical. This makes the default bind-
ings dangerous: Be careful not to type C-a C-4 when selecting window no.
4. Use the empty bind command (as in bind '^\') to remove a key bind-
ing.
readbuf [encoding] [filename]
Reads the contents of the specified file into the paste buffer. You can
tell screen the encoding of the file via the -e option. If no file is
specified, the screen-exchange filename is used. See also bufferfile
command.
readreg [encoding] [register [filename]]
Does one of two things, dependent on number of arguments: with zero or
one arguments it duplicates the paste buffer contents into the register
specified or entered at the prompt. With two arguments it reads the con-
tents of the named file into the register, just as readbuf reads the
screen-exchange file into the paste buffer. You can tell screen the en-
coding of the file via the -e option. The following example will paste
the system's password file into the screen window (using register p,
where a copy remains):
C-a : readreg p /etc/passwd
C-a : paste p
redisplay
Redisplay the current window. Needed to get a full redisplay when in
partial redraw mode.
register [-eencoding]key-string
Save the specified string to the register key. The encoding of the
string can be specified via the -e option. See also the paste command.
remove
Kill the current region. This is a no-op if there is only one region.
removebuf
Unlinks the screen-exchange file used by the commands writebuf and read-
buf.
rendition [ bell | monitor | silence | so ] attr [ color ]
Change the way screen renders the titles of windows that have monitor or
bell flags set in caption or hardstatus or windowlist. See the STRING
ESCAPES chapter for the syntax of the modifiers. The default for moni-
tor is currently =b (bold, active colors), for bell =ub (underline,
bold and active colors), and =u for silence.
reset
Reset the virtual terminal to its power-on values. Useful when strange
settings (like scroll regions or graphics character set) are left over
from an application.
resize [-h|-v|-b|-l|-p] [[+|-] n[%] |=|max|min|_|0]
Resize the current region. The space will be removed from or added to
the surrounding regions depending on the order of the splits. The
available options for resizing are `-h'(horizontal), `-v'(vertical),
`-b'(both), `-l'(local to layer), and `-p'(perpendicular). Horizontal
resizes will add or remove width to a region, vertical will add or re-
move height, and both will add or remove size from both dimensions. Lo-
cal and perpendicular are similar to horizontal and vertical, but they
take in account of how a region was split. If a region's last split was
horizontal, a local resize will work like a vertical resize. If a re-
gion's last split was vertical, a local resize will work like a horizon-
tal resize. Perpendicular resizes work in opposite of local resizes. If
no option is specified, local is the default.
The amount of lines to add or remove can be expressed a couple of dif-
ferent ways. By specifying a number n by itself will resize the region
by that absolute amount. You can specify a relative amount by prefixing
a plus `+' or minus `-' to the amount, such as adding +n lines or remov-
ing -n lines. Resizing can also be expressed as an absolute or relative
percentage by postfixing a percent sign `%'. Using zero `0' is a synonym
for `min' and using an underscore `_' is a synonym for `max'.
Some examples are:
resize +N
increase current region by N
resize -N
decrease current region by N
resize N
set current region to N
resize 20%
set current region to 20% of original size
resize +20%
increase current region by 20%
resize -b =
make all windows equally
resize max
maximize current region
resize min
minimize current region
Without any arguments, screen will prompt for how you would like to re-
size the current region.
See focusminsize if you want to restrict the minimum size a region can
have.
screen [-opts] [n] [cmd [args]|//group]
Establish a new window. The flow-control options (-f, -fn and -fa), ti-
tle (a.k.a.) option (-t), login options (-l and -ln) , terminal type op-
tion (-T <term>), the all-capability-flag (-a) and scrollback option (-h
<num>) may be specified with each command. The option (-M) turns moni-
toring on for this window. The option (-L) turns output logging on for
this window. If an optional number n in the range 0..MAXWIN-1 is given,
the window number n is assigned to the newly created window (or, if this
number is already in-use, the next available number). If a command is
specified after screen, this command (with the given arguments) is
started in the window; otherwise, a shell is created. If //group is
supplied, a container-type window is created in which other windows may
be created inside it.
Thus, if your .screenrc contains the lines
# example for .screenrc:
screen 1
screen -fn -t foobar -L 2 telnet foobar
screen creates a shell window (in window #1) and a window with a TELNET
connection to the machine foobar (with no flow-control using the title
foobar in window #2) and will write a logfile (screenlog.2) of the tel-
net session. Note, that unlike previous versions of screen no addi-
tional default window is created when screen commands are included in
your .screenrc file. When the initialization is completed, screen
switches to the last window specified in your .screenrc file or, if
none, opens a default window #0.
Screen has built in some functionality of cu and telnet. See also chap-
ter WINDOW TYPES.
scrollback num
Set the size of the scrollback buffer for the current windows to num
lines. The default scrollback is 100 lines. See also the defscrollback
command and use info to view the current setting. To access and use the
contents in the scrollback buffer, use the copy command.
select [WindowID]
Switch to the window identified by WindowID. This can be a prefix of a
window title (alphanumeric window name) or a window number. The parame-
ter is optional and if omitted, you get prompted for an identifier.
When a new window is established, the first available number is assigned
to this window. Thus, the first window can be activated by select 0.
The number of windows is set by the MAXWIN configuration parameter
(which defaults to 100), but it can be changed by using `maxwin' com-
mand. There are two special WindowIDs, - selects the internal blank
window and . selects the current window. The latter is useful if used
with screen's -X option.
sessionname [name]
Rename the current session. Note, that for screen -list the name shows
up with the process-id prepended. If the argument name is omitted, the
name of this session is displayed. Caution: The $STY environment vari-
ables will still reflect the old name in pre-existing shells. This may
result in confusion. Use of this command is generally discouraged. Use
the -S command-line option if you want to name a new session. The de-
fault is constructed from the tty and host names.
setenv [var [string]]
Set the environment variable var to value string. If only var is speci-
fied, the user will be prompted to enter a value. If no parameters are
specified, the user will be prompted for both variable and value. The
environment is inherited by all subsequently forked shells.
setsid [ on | off ]
Normally screen uses different sessions and process groups for the win-
dows. If setsid is turned off, this is not done anymore and all windows
will be in the same process group as the screen backend process. This
also breaks job-control, so be careful. The default is on, of course.
This command is probably useful only in rare circumstances.
shell command
Set the command to be used to create a new shell. This overrides the
value of the environment variable $SHELL. This is useful if you'd like
to run a tty-enhancer which is expecting to execute the program speci-
fied in $SHELL. If the command begins with a '-' character, the shell
will be started as a login-shell. Typical shells do only minimal ini-
tialization when not started as a login-shell. E.g. Bash will not read
your ~/.bash_profile unless it is a login-shell.
shelltitle title
Set the title for all shells created during startup or by the C-A C-c
command. For details about what a title is, see the discussion entitled
TITLES (naming windows).
silence [ on | off | sec ]
Toggles silence monitoring of windows. When silence is turned on and an
affected window is switched into the background, you will receive the
silence notification message in the status line after a specified period
of inactivity (silence). The default timeout can be changed with the
`silencewait' command or by specifying a number of seconds instead of
`on' or `off'. Silence is initially off for all windows.
silencewait sec
Define the time that all windows monitored for silence should wait be-
fore displaying a message. Default 30 seconds.
sleep num
This command will pause the execution of a .screenrc file for num sec-
onds. Keyboard activity will end the sleep. It may be used to give
users a chance to read the messages output by echo.
slowpaste msec
Define the speed at which text is inserted into the current window by
the paste ("C-a ]") command. If the slowpaste value is nonzero text is
written character by character. screen will make a pause of msec mil-
liseconds after each single character write to allow the application to
process its input. Only use slowpaste if your underlying system exposes
flow control problems while pasting large amounts of text.
sort
Sort the windows in alphabetical order of the window tiles.
source file
Read and execute commands from file file. Source commands may be nested
to a maximum recursion level of ten. If file is not an absolute path and
screen is already processing a source command, the parent directory of
the running source command file is used to search for the new command
file before screen's current directory.
Note that termcap/terminfo/termcapinfo commands only work at startup and
reattach time, so they must be reached via the default screenrc files to
have an effect.
sorendition [attr[color]]
This command is deprecated. See "rendition so" instead.
split[-v]
Split the current region into two new ones. All regions on the display
are resized to make room for the new region. The blank window is dis-
played in the new region. The default is to create a horizontal split,
putting the new regions on the top and bottom of each other. Using `-v'
will create a vertical split, causing the new regions to appear side by
side of each other. Use the remove or the only command to delete re-
gions. Use focus to toggle between regions.
When a region is split opposite of how it was previously split (that is,
vertical then horizontal or horizontal then vertical), a new layer is
created. The layer is used to group together the regions that are split
the same. Normally, as a user, you should not see nor have to worry
about layers, but they will affect how some commands (focus and resize)
behave.
With this current implementation of screen, scrolling data will appear
much slower in a vertically split region than one that is not. This
should be taken into consideration if you need to use system commands
such as cat or tail -f.
startup_message [ on | off ]
Select whether you want to see the copyright notice during startup. De-
fault is `on', as you probably noticed.
status [ top | up | down | bottom ] [ left | right ]
The status window by default is in bottom-left corner. This command can
move status messages to any corner of the screen. top is the same as up,
down is the same as bottom.
stuff [string]
Stuff the string string in the input buffer of the current window. This
is like the paste command but with much less overhead. Without a para-
meter, screen will prompt for a string to stuff. You cannot paste large
buffers with the stuff command. It is most useful for key bindings. See
also bindkey.
su [username [password [password2]]]
Substitute the user of a display. The command prompts for all parameters
that are omitted. If passwords are specified as parameters, they have to
be specified un-crypted. The first password is matched against the sys-
tems passwd database, the second password is matched against the screen
password as set with the commands acladd or password. Su may be useful
for the screen administrator to test multiuser setups. When the identi-
fication fails, the user has access to the commands available for user
nobody. These are detach, license, version, help and displays.
suspend
Suspend screen. The windows are in the `detached' state, while screen
is suspended. This feature relies on the shell being able to do job con-
trol.
term term
In each window's environment screen opens, the $TERM variable is set to
screen by default. But when no description for screen is installed in
the local termcap or terminfo data base, you set $TERM to - say - vt100.
This won't do much harm, as screen is VT100/ANSI compatible. The use of
the term command is discouraged for non-default purpose. That is, one
may want to specify special $TERM settings (e.g. vt100) for the next
screen rlogin othermachine command. Use the command screen -T vt100
rlogin othermachine rather than setting and resetting the default.
termcap term terminal-tweaks[window-tweaks]
terminfo term terminal-tweaks[window-tweaks]
termcapinfo term terminal-tweaks[window-tweaks]
Use this command to modify your terminal's termcap entry without going
through all the hassles involved in creating a custom termcap entry.
Plus, you can optionally customize the termcap generated for the win-
dows. You have to place these commands in one of the screenrc startup
files, as they are meaningless once the terminal emulator is booted.
If your system uses the terminfo database rather than termcap, screen
will understand the `terminfo' command, which has the same effects as
the `termcap' command. Two separate commands are provided, as there are
subtle syntactic differences, e.g. when parameter interpolation (using
`%') is required. Note that termcap names of the capabilities have to be
used with the `terminfo' command.
In many cases, where the arguments are valid in both terminfo and term-
cap syntax, you can use the command `termcapinfo', which is just a
shorthand for a pair of `termcap' and `terminfo' commands with identical
arguments.
The first argument specifies which terminal(s) should be affected by
this definition. You can specify multiple terminal names by separating
them with `|'s. Use `*' to match all terminals and `vt*' to match all
terminals that begin with vt.
Each tweak argument contains one or more termcap defines (separated by
`:'s) to be inserted at the start of the appropriate termcap entry, en-
hancing it or overriding existing values. The first tweak modifies your
terminal's termcap, and contains definitions that your terminal uses to
perform certain functions. Specify a null string to leave this un-
changed (e.g. ''). The second (optional) tweak modifies all the window
termcaps, and should contain definitions that screen understands (see
the VIRTUAL TERMINAL section).
Some examples:
termcap xterm* LP:hs@
Informs screen that all terminals that begin with `xterm' have firm
auto-margins that allow the last position on the screen to be updated
(LP), but they don't really have a status line (no 'hs' - append `@' to
turn entries off). Note that we assume `LP' for all terminal names that
start with vt, but only if you don't specify a termcap command for that
terminal.
termcap vt* LP
termcap vt102|vt220 Z0=\E[?3h:Z1=\E[?3l
Specifies the firm-margined `LP' capability for all terminals that begin
with `vt', and the second line will also add the escape-sequences to
switch into (Z0) and back out of (Z1) 132-character-per-line mode if
this is a VT102 or VT220. (You must specify Z0 and Z1 in your termcap
to use the width-changing commands.)
termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4
This leaves your vt100 termcap alone and adds the function key labels to
each window's termcap entry.
termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P
Takes a h19 or z19 termcap and turns off auto-margins (am@) and enables
the insert mode (im) and end-insert (ei) capabilities (the `@' in the
`im' string is after the `=', so it is part of the string). Having the
`im' and `ei' definitions put into your terminal's termcap will cause
screen to automatically advertise the character-insert capability in
each window's termcap. Each window will also get the delete-character
capability (dc) added to its termcap, which screen will translate into a
line-update for the terminal (we're pretending it doesn't support char-
acter deletion).
If you would like to fully specify each window's termcap entry, you
should instead set the $SCREENCAP variable prior to running screen. See
the discussion on the VIRTUAL TERMINAL in this manual, and the term-
cap(5) man page for more information on termcap definitions.
time [string]
Uses the message line to display the time of day, the host name, and the
load averages over 1, 5, and 15 minutes (if this is available on your
system). For window specific information, use info.
If a string is specified, it changes the format of the time report like
it is described in the STRING ESCAPES chapter. Screen uses a default of
"%c:%s %M %d %H%? %l%?".
title [windowtitle]
Set the name of the current window to windowtitle. If no name is speci-
fied, screen prompts for one. This command was known as `aka' in previ-
ous releases.
unbindall
Unbind all the bindings. This can be useful when screen is used solely
for its detaching abilities, such as when letting a console application
run as a daemon. If, for some reason, it is necessary to bind commands
after this, use 'screen -X'.
unsetenv var
Unset an environment variable.
utf8 [ on | off [ on | off ]]
Change the encoding used in the current window. If utf8 is enabled, the
strings sent to the window will be UTF-8 encoded and vice versa. Omit-
ting the parameter toggles the setting. If a second parameter is given,
the display's encoding is also changed (this should rather be done with
screen's -U option). See also defutf8, which changes the default set-
ting of a new window.
vbell [ on | off ]
Sets the visual bell setting for this window. Omitting the parameter
toggles the setting. If vbell is switched on, but your terminal does not
support a visual bell, a `vbell-message' is displayed in the status line
when the bell character (^G) is received. Visual bell support of a ter-
minal is defined by the termcap variable `vb' (terminfo: 'flash').
Per default, vbell is off, thus the audible bell is used. See also
`bell_msg'.
vbell_msg [message]
Sets the visual bell message. message is printed to the status line if
the window receives a bell character (^G), vbell is set to on, but the
terminal does not support a visual bell. The default message is Wuff,
Wuff!!. Without a parameter, the current message is shown.
vbellwait sec
Define a delay in seconds after each display of screen's visual bell
message. The default is 1 second.
verbose [ on | off ]
If verbose is switched on, the command name is echoed, whenever a window
is created (or resurrected from zombie state). Default is off. Without
a parameter, the current setting is shown.
version
Print the current version and the compile date in the status line.
wall message
Write a message to all displays. The message will appear in the termi-
nal's status line.
width [-w|-d] [cols [lines]]
Toggle the window width between 80 and 132 columns or set it to cols
columns if an argument is specified. This requires a capable terminal
and the termcap entries Z0 and Z1. See the termcap command for more in-
formation. You can also specify a new height if you want to change both
values. The -w option tells screen to leave the display size unchanged
and just set the window size, -d vice versa.
windowlist [ -b ] [ -m ] [ -g ]
windowlist string [string]
windowlist title [title]
Display all windows in a table for visual window selection. If screen
was in a window group, screen will back out of the group and then dis-
play the windows in that group. If the -b option is given, screen will
switch to the blank window before presenting the list, so that the cur-
rent window is also selectable. The -m option changes the order of the
windows, instead of sorting by window numbers screen uses its internal
most-recently-used list. The -g option will show the windows inside any
groups in that level and downwards.
The following keys are used to navigate in windowlist:
─────────────────────────────────────────────────────────────────────
k, C-p, or up Move up one line.
─────────────────────────────────────────────────────────────────────
j, C-n, or down Move down one line.
─────────────────────────────────────────────────────────────────────
C-g or escape Exit windowlist.
─────────────────────────────────────────────────────────────────────
C-a or home Move to the first line.
─────────────────────────────────────────────────────────────────────
C-e or end Move to the last line.
─────────────────────────────────────────────────────────────────────
C-u or C-d Move one half page up or down.
─────────────────────────────────────────────────────────────────────
C-b or C-f Move one full page up or down.
─────────────────────────────────────────────────────────────────────
0..9 Using the number keys, move to the selected line.
─────────────────────────────────────────────────────────────────────
mouseclick Move to the selected line. Available when mouse-
track is set to on
─────────────────────────────────────────────────────────────────────
/ Search.
─────────────────────────────────────────────────────────────────────
n Repeat search in the forward direction.
─────────────────────────────────────────────────────────────────────
N Repeat search in the backward direction.
─────────────────────────────────────────────────────────────────────
m Toggle MRU.
─────────────────────────────────────────────────────────────────────
g Toggle group nesting.
─────────────────────────────────────────────────────────────────────
a All window view.
─────────────────────────────────────────────────────────────────────
C-h or backspace Back out the group.
─────────────────────────────────────────────────────────────────────
, Switch numbers with the previous window.
─────────────────────────────────────────────────────────────────────
. Switch numbers with the next window.
─────────────────────────────────────────────────────────────────────
K Kill that window.
─────────────────────────────────────────────────────────────────────
space or enter Select that window.
─────────────────────────────────────────────────────────────────────
The table format can be changed with the string and title option, the
title is displayed as table heading, while the lines are made by using
the string setting. The default setting is Num Name%=Flags for the title
and %3n %t%=%f for the lines. See the STRING ESCAPES chapter for more
codes (e.g. color settings).
Windowlist needs a region size of at least 10 characters wide and 6
characters high in order to display.
windows [ string ]
Uses the message line to display a list of all the windows. Each window
is listed by number with the name of process that has been started in
the window (or its title); the current window is marked with a `*'; the
previous window is marked with a `-'; all the windows that are logged in
are marked with a `$'; a background window that has received a bell is
marked with a `!'; a background window that is being monitored and has
had activity occur is marked with an `@'; a window which has output log-
ging turned on is marked with `(L)'; windows occupied by other users are
marked with `&'; windows in the zombie state are marked with `Z'. If
this list is too long to fit on the terminal's status line only the por-
tion around the current window is displayed. The optional string para-
meter follows the STRING ESCAPES format. If string parameter is passed,
the output size is unlimited. The default command without any parameter
is limited to a size of 1024 bytes.
wrap [ on | off ]
Sets the line-wrap setting for the current window. When line-wrap is
on, the second consecutive printable character output at the last column
of a line will wrap to the start of the following line. As an added
feature, backspace (^H) will also wrap through the left margin to the
previous line. Default is `on'. Without any options, the state of wrap
is toggled.
writebuf [-e encoding] [filename]
Writes the contents of the paste buffer to the specified file, or the
public accessible screen-exchange file if no filename is given. This is
thought of as a primitive means of communication between screen users on
the same host. If an encoding is specified the paste buffer is recoded
on the fly to match the encoding. The filename can be set with the
bufferfile command and defaults to /tmp/screen-exchange.
writelock [ on | off | auto]
In addition to access control lists, not all users may be able to write
to the same window at once. Per default, writelock is in `auto' mode and
grants exclusive input permission to the user who is the first to switch
to the particular window. When he leaves the window, other users may ob-
tain the writelock (automatically). The writelock of the current window
is disabled by the command writelock off. If the user issues the command
writelock on he keeps the exclusive write permission while switching to
other windows.
xoff
xon
Insert a CTRL-s / CTRL-q character to the stdin queue of the current
window.
zmodem [ off | auto | catch | pass ]
zmodem sendcmd [string]
zmodem recvcmd [string]
Define zmodem support for screen. Screen understands two different modes
when it detects a zmodem request: pass and catch. If the mode is set to
pass, screen will relay all data to the attacher until the end of the
transmission is reached. In catch mode screen acts as a zmodem endpoint
and starts the corresponding rz/sz commands. If the mode is set to auto,
screen will use catch if the window is a tty (e.g. a serial line), oth-
erwise it will use pass.
You can define the templates screen uses in catch mode via the second
and the third form.
Note also that this is an experimental feature.
zombie [keys[onerror]]
Per default screen windows are removed from the window list as soon as
the windows process (e.g. shell) exits. When a string of two keys is
specified to the zombie command, `dead' windows will remain in the list.
The kill command may be used to remove such a window. Pressing the first
key in the dead window has the same effect. When pressing the second
key, screen will attempt to resurrect the window. The process that was
initially running in the window will be launched again. Calling zombie
without parameters will clear the zombie setting, thus making windows
disappear when their process exits.
As the zombie-setting is manipulated globally for all windows, this com-
mand should probably be called defzombie, but it isn't.
Optionally you can put the word onerror after the keys. This will cause
screen to monitor exit status of the process running in the window. If
it exits normally ('0'), the window disappears. Any other exit value
causes the window to become a zombie.
zombie_timeout[seconds]
Per default screen windows are removed from the window list as soon as
the windows process (e.g. shell) exits. If zombie keys are defined (com-
pare with above zombie command), it is possible to also set a timeout
when screen tries to automatically reconnect a dead screen window.
THE MESSAGE LINE
Screen displays informational messages and other diagnostics in a mes-
sage line. While this line is distributed to appear at the bottom of
the screen, it can be defined to appear at the top of the screen during
compilation. If your terminal has a status line defined in its termcap,
screen will use this for displaying its messages, otherwise a line of
the current screen will be temporarily overwritten and output will be
momentarily interrupted. The message line is automatically removed after
a few seconds delay, but it can also be removed early (on terminals
without a status line) by beginning to type.
The message line facility can be used by an application running in the
current window by means of the ANSI Privacy message control sequence.
For instance, from within the shell, try something like:
echo '<esc>^Hello world from window '$WINDOW'<esc>\\'
where '<esc>' is an escape, '^' is a literal up-arrow, and '\\' turns
into a single backslash.
WINDOW TYPES
Screen provides three different window types. New windows are created
with screen's screen command (see also the entry in chapter CUSTOMIZA-
TION). The first parameter to the screen command defines which type of
window is created. The different window types are all special cases of
the normal type. They have been added in order to allow screen to be
used efficiently as a console multiplexer with 100 or more windows.
• The normal window contains a shell (default, if no parameter is
given) or any other system command that could be executed from a
shell (e.g. slogin, etc...)
• If a tty (character special device) name (e.g. /dev/ttya) is speci-
fied as the first parameter, then the window is directly connected to
this device. This window type is similar to screen cu -l /dev/ttya.
Read and write access is required on the device node, an exclusive
open is attempted on the node to mark the connection line as busy.
An optional parameter is allowed consisting of a comma separated list
of flags in the notation used by stty(1):
<baud_rate>
Usually 300, 1200, 9600 or 19200. This affects transmission as
well as receive speed.
cs8 or cs7
Specify the transmission of eight (or seven) bits per byte.
cstopb or -cstopb
Specify two stop bits per character (one with '-')
parenb or -parenb
Generate parity bit in output and expect parity bit in input
parodd or -parodd
Set odd parity (or even parity with '-')
ixon or -ixon
Enables (or disables) software flow-control (CTRL-S/CTRL-Q)
for sending data.
ixoff or -ixoff
Enables (or disables) software flow-control for receiving
data.
istrip or -istrip
Clear (or keep) the eight bit in each received byte.
You may want to specify as many of these options as applicable. Un-
specified options cause the terminal driver to make up the parameter
values of the connection. These values are system dependent and may
be in defaults or values saved from a previous connection.
For tty windows, the info command shows some of the modem control
lines in the status line. These may include `RTS', `CTS', 'DTR',
`DSR', `CD' and more. This depends on the available ioctl()'s and
system header files as well as the on the physical capabilities of
the serial board. Signals that are logical low (inactive) have their
name preceded by an exclamation mark (!), otherwise the signal is
logical high (active). Signals not supported by the hardware but
available to the ioctl() interface are usually shown low.
When the CLOCAL status bit is true, the whole set of modem signals is
placed inside curly braces ({ and }). When the CRTSCTS or TIOCSOFT-
CAR bit is set, the signals `CTS' or `CD' are shown in parenthesis,
respectively.
For tty windows, the command break causes the Data transmission line
(TxD) to go low for a specified period of time. This is expected to
be interpreted as break signal on the other side. No data is sent
and no modem control line is changed when a break is issued.
• If the first parameter is //telnet, the second parameter is expected
to be a host name, and an optional third parameter may specify a TCP
port number (default decimal 23). Screen will connect to a server
listening on the remote host and use the telnet protocol to communi-
cate with that server.
For telnet windows, the command info shows details about the connection
in square brackets ([ and ]) at the end of the status line.
b BINARY. The connection is in binary mode.
e ECHO. Local echo is disabled.
c SGA. The connection is in `character mode' (default: `line
mode').
t TTYPE. The terminal type has been requested by the remote
host. Screen sends the name screen unless instructed oth-
erwise (see also the command `term').
w NAWS. The remote site is notified about window size
changes.
f LFLOW. The remote host will send flow control information.
(Ignored at the moment.)
Additional flags for debugging are x, t and n (XDISPLOC, TSPEED
and NEWENV).
For telnet windows, the command break sends the telnet code IAC
BREAK (decimal 243) to the remote host.
This window type is only available if screen was compiled with
the ENABLE_TELNET option defined.
STRING ESCAPES
Screen provides an escape mechanism to insert information like the cur-
rent time into messages or file names. The escape character is '%' with
one exception: inside of a window's hardstatus '^%' ('^E') is used in-
stead.
Here is the full list of supported escapes:
% the escape character itself
E sets %? to true if the escape character has been pressed.
e encoding
f flags of the window, see windows for meanings of the various
flags
F sets %? to true if the window has the focus
h hardstatus of the window
H hostname of the system
n window number
P sets %? to true if the current region is in copy/paste mode
S session name
s window size
t window title
u all other users on this window
w all window numbers and names. With '-' qualifier: up to the cur-
rent window; with '+' qualifier: starting with the window after
the current one.
W all window numbers and names except the current one
x the executed command including arguments running in this windows
X the executed command without arguments running in this windows
? the part to the next '%?' is displayed only if a '%' escape in-
side the part expands to a non-empty string
: else part of '%?'
= pad the string to the display's width (like TeX's hfill). If a
number is specified, pad to the percentage of the window's width.
A '0' qualifier tells screen to treat the number as absolute po-
sition. You can specify to pad relative to the last absolute pad
position by adding a '+' qualifier or to pad relative to the
right margin by using '-'. The padding truncates the string if
the specified position lies before the current position. Add the
'L' qualifier to change this.
< same as '%=' but just do truncation, do not fill with spaces
> mark the current text position for the next truncation. When
screen needs to do truncation, it tries to do it in a way that
the marked position gets moved to the specified percentage of the
output area. (The area starts from the last absolute pad position
and ends with the position specified by the truncation operator.)
The 'L' qualifier tells screen to mark the truncated parts with
'...'.
{ attribute/color modifier string terminated by the next }
` Substitute with the output of a 'backtick' command. The length
qualifier is misused to identify one of the commands.
The 'c' and 'C' escape may be qualified with a '0' to make screen use
zero instead of space as fill character. The '0' qualifier also makes
the '=' escape use absolute positions. The 'n' and '=' escapes under-
stand a length qualifier (e.g. '%3n'), 'D' and 'M' can be prefixed with
'L' to generate long names, 'w' and 'W' also show the window flags if
'L' is given.
An attribute/color modifier is used to change the attributes or the
color settings. Its format is [attribute modifier] [color description].
The attribute modifier must be prefixed by a change type indicator if it
can be confused with a color description. The following change types are
known:
+ add the specified set to the current attributes
- remove the set from the current attributes
! invert the set in the current attributes
= change the current attributes to the specified set
The attribute set can either be specified as a hexadecimal number or a
combination of the following letters:
d dim
u underline
b bold
r reverse
s /standout
B blinking
Colors are coded either as a hexadecimal number or two letters specify-
ing the desired background and foreground color (in that order). The
following colors are known:
k black
r red
g green
y yellow
b blue
m magenta
c cyan
w white
d default color
. leave color unchanged
The capitalized versions of the letter specify bright colors. You can
also use the pseudo-color 'i' to set just the brightness and leave the
color unchanged.
A one digit/letter color description is treated as foreground or back-
ground color dependent on the current attributes: if reverse mode is
set, the background color is changed instead of the foreground color.
If you don't like this, prefix the color with a .. If you want the same
behavior for two-letter color descriptions, also prefix them with a ..
As a special case, %{-} restores the attributes and colors that were set
before the last change was made (i.e., pops one level of the color-
change stack).
Examples:
G set color to bright green
+b r use bold red
= yd clear all attributes, write in default color on yellow back-
ground.
%-Lw%{= BW}%50>%n%f* %t%{-}%+Lw%<
The available windows centered at the current window and trun-
cated to the available width. The current window is displayed
white on blue. This can be used with hardstatus alwayslastline.
%?%F%{.R.}%?%3n %t%? [%h]%?
The window number and title and the window's hardstatus, if one
is set. Also use a red background if this is the active focus.
Useful for caption string.
FLOW-CONTROL
Each window has a flow-control setting that determines how screen deals
with the XON and XOFF characters (and perhaps the interrupt character).
When flow-control is turned off, screen ignores the XON and XOFF charac-
ters, which allows the user to send them to the current program by sim-
ply typing them (useful for the emacs editor, for instance). The trade-
off is that it will take longer for output from a normal program to
pause in response to an XOFF. With flow-control turned on, XON and XOFF
characters are used to immediately pause the output of the current win-
dow. You can still send these characters to the current program, but
you must use the appropriate two-character screen commands (typically C-
a q (xon) and C-a s (xoff)). The xon/xoff commands are also useful for
typing C-s and C-q past a terminal that intercepts these characters.
Each window has an initial flow-control value set with either the -f op-
tion or the defflow .screenrc command. Per default the windows are set
to automatic flow-switching. It can then be toggled between the three
states 'fixed on', 'fixed off' and 'automatic' interactively with the
flow command bound to "C-a f".
The automatic flow-switching mode deals with flow control using the TI-
OCPKT mode (like rlogin does). If the tty driver does not support TI-
OCPKT, screen tries to find out the right mode based on the current set-
ting of the application keypad - when it is enabled, flow-control is
turned off and visa versa. Of course, you can still manipulate flow-
control manually when needed.
If you're running with flow-control enabled and find that pressing the
interrupt key (usually C-c) does not interrupt the display until another
6-8 lines have scrolled by, try running screen with the interrupt option
(add the interrupt flag to the flow command in your .screenrc, or use
the -i command-line option). This causes the output that screen has ac-
cumulated from the interrupted program to be flushed. One disadvantage
is that the virtual terminal's memory contains the non-flushed version
of the output, which in rare cases can cause minor inaccuracies in the
output. For example, if you switch screens and return, or update the
screen with C-a l you would see the version of the output you would have
gotten without interrupt being on. Also, you might need to turn off
flow-control (or use auto-flow mode to turn it off automatically) when
running a program that expects you to type the interrupt character as
input, as it is possible to interrupt the output of the virtual terminal
to your physical terminal when flow-control is enabled. If this hap-
pens, a simple refresh of the screen with C-a l will restore it. Give
each mode a try, and use whichever mode you find more comfortable.
TITLES (naming windows)
You can customize each window's name in the window display (viewed with
the windows command (C-a w)) by setting it with one of the title com-
mands. Normally the name displayed is the actual command name of the
program created in the window. However, it is sometimes useful to dis-
tinguish various programs of the same name or to change the name on-the-
fly to reflect the current state of the window.
The default name for all shell windows can be set with the shelltitle
command in the .screenrc file, while all other windows are created with
a screen command and thus can have their name set with the -t option.
Interactively, there is the title-string escape-sequence
(<esc>kname<esc>\) and the title command (C-a A). The former can be
output from an application to control the window's name under software
control, and the latter will prompt for a name when typed. You can also
bind pre-defined names to keys with the title command to set things
quickly without prompting. Changing title by this escape sequence can be
controlled by defdynamictitle and dynamictitle commands.
Finally, screen has a shell-specific heuristic that is enabled by set-
ting the window's name to search|name and arranging to have a null title
escape-sequence output as a part of your prompt. The search portion
specifies an end-of-prompt search string, while the name portion speci-
fies the default shell name for the window. If the name ends in a `:'
screen will add what it believes to be the current command running in
the window to the end of the window's shell name (e.g. name:cmd). Oth-
erwise the current command name supersedes the shell name while it is
running.
Here's how it works: you must modify your shell prompt to output a null
title-escape-sequence (<esc>k<esc>\) as a part of your prompt. The last
part of your prompt must be the same as the string you specified for the
search portion of the title. Once this is set up, screen will use the
title-escape-sequence to clear the previous command name and get ready
for the next command. Then, when a newline is received from the shell,
a search is made for the end of the prompt. If found, it will grab the
first word after the matched string and use it as the command name. If
the command name begins with either '!', '%', or '^' screen will use the
first word on the following line (if found) in preference to the just-
found name. This helps csh users get better command names when using
job control or history recall commands.
Here's some .screenrc examples:
screen -t top 2 nice top
Adding this line to your .screenrc would start a nice-d version of the
top command in window 2 named top rather than nice.
shelltitle '> |csh'
screen 1
These commands would start a shell with the given shelltitle. The title
specified is an auto-title that would expect the prompt and the typed
command to look something like the following:
/usr/joe/src/dir> trn
(it looks after the '> ' for the command name). The window status would
show the name trn while the command was running, and revert to csh upon
completion.
bind R screen -t '% |root:' su
Having this command in your .screenrc would bind the key sequence C-a R
to the su command and give it an auto-title name of root:. For this
auto-title to work, the screen could look something like this:
% !em
emacs file.c
Here the user typed the csh history command !em which ran the previously
entered emacs command. The window status would show root:emacs during
the execution of the command, and revert to simply root: at its comple-
tion.
bind o title
bind E title ""
bind u title (unknown)
The first binding doesn't have any arguments, so it would prompt you for
a title when you type C-a o. The second binding would clear an auto-ti-
tle's current setting (C-a E). The third binding would set the current
window's title to (unknown) (C-a u).
One thing to keep in mind when adding a null title-escape-sequence to
your prompt is that some shells (like the csh) count all the non-control
characters as part of the prompt's length. If these invisible charac-
ters aren't a multiple of 8 then backspacing over a tab will result in
an incorrect display. One way to get around this is to use a prompt
like this:
set prompt='^[[0000m^[k^[\% '
The escape-sequence <esc>[0000m not only normalizes the character at-
tributes, but all the zeros round the length of the invisible characters
up to 8. Bash users will probably want to echo the escape sequence in
the PROMPT_COMMAND:
PROMPT_COMMAND='printf "\033k\033\134"'
(I used \134 to output a `\' because of a bug in bash v1.04).
THE VIRTUAL TERMINAL
Each window in a screen session emulates a VT100 terminal, with some ex-
tra functions added. The VT100 emulator is hard-coded, no other terminal
types can be emulated.
Usually screen tries to emulate as much of the VT100/ANSI standard as
possible. But if your terminal lacks certain capabilities, the emulation
may not be complete. In these cases screen has to tell the applications
that some of the features are missing. This is no problem on machines
using termcap, because screen can use the $TERMCAP variable to customize
the standard screen termcap.
But if you do a rlogin on another machine or your machine supports only
terminfo this method fails. Because of this, screen offers a way to deal
with these cases. Here is how it works:
When screen tries to figure out a terminal name for itself, it first
looks for an entry named screen.<term>, where <term> is the contents of
your $TERM variable. If no such entry exists, screen tries screen (or
screen-w if the terminal is wide (132 cols or more)). If even this en-
try cannot be found, vt100 is used as a substitute.
The idea is that if you have a terminal which doesn't support an impor-
tant feature (e.g. delete char or clear to EOS) you can build a new
termcap/terminfo entry for screen (named screen.<dumbterm>) in which
this capability has been disabled. If this entry is installed on your
machines you are able to do a rlogin and still keep the correct term-
cap/terminfo entry. The terminal name is put in the $TERM variable of
all new windows. Screen also sets the $TERMCAP variable reflecting the
capabilities of the virtual terminal emulated. Notice that, however, on
machines using the terminfo database this variable has no effect. Fur-
thermore, the variable $WINDOW is set to the window number of each win-
dow.
The actual set of capabilities supported by the virtual terminal depends
on the capabilities supported by the physical terminal. If, for in-
stance, the physical terminal does not support underscore mode, screen
does not put the `us' and `ue' capabilities into the window's $TERMCAP
variable, accordingly. However, a minimum number of capabilities must
be supported by a terminal in order to run screen; namely scrolling,
clear screen, and direct cursor addressing (in addition, screen does not
run on hardcopy terminals or on terminals that over-strike).
Also, you can customize the $TERMCAP value used by screen by using the
termcap .screenrc command, or by defining the variable $SCREENCAP prior
to startup. When the latter is defined, its value will be copied verba-
tim into each window's $TERMCAP variable. This can either be the full
terminal definition, or a filename where the terminal screen (and/or
screen-w) is defined.
Note that screen honors the terminfo .screenrc command if the system
uses the terminfo database rather than termcap.
When the boolean `G0' capability is present in the termcap entry for the
terminal on which screen has been called, the terminal emulation of
screen supports multiple character sets. This allows an application to
make use of, for instance, the VT100 graphics character set or national
character sets. The following control functions from ISO 2022 are sup-
ported: lock shift G0 (SI), lock shift G1 (SO), lock shift G2, lock
shift G3, single shift G2, and single shift G3. When a virtual terminal
is created or reset, the ASCII character set is designated as G0 through
G3. When the `G0' capability is present, screen evaluates the capabili-
ties `S0', `E0', and `C0' if present. `S0' is the sequence the terminal
uses to enable and start the graphics character set rather than SI.
`E0' is the corresponding replacement for SO. `C0' gives a character by
character translation string that is used during semi-graphics mode.
This string is built like the `acsc' terminfo capability.
When the `po' and `pf' capabilities are present in the terminal's term-
cap entry, applications running in a screen window can send output to
the printer port of the terminal. This allows a user to have an appli-
cation in one window sending output to a printer connected to the termi-
nal, while all other windows are still active (the printer port is en-
abled and disabled again for each chunk of output). As a side-effect,
programs running in different windows can send output to the printer si-
multaneously. Data sent to the printer is not displayed in the window.
The info command displays a line starting `PRIN' while the printer is
active.
Screen maintains a hardstatus line for every window. If a window gets
selected, the display's hardstatus will be updated to match the window's
hardstatus line. If the display has no hardstatus the line will be dis-
played as a standard screen message. The hardstatus line can be changed
with the ANSI Application Program Command (APC): ESC_<string>ESC\. As a
convenience for xterm users the sequence ESC]0..2;<string>^G is also ac-
cepted.
Some capabilities are only put into the $TERMCAP variable of the virtual
terminal if they can be efficiently implemented by the physical termi-
nal. For instance, `dl' (delete line) is only put into the $TERMCAP
variable if the terminal supports either delete line itself or scrolling
regions. Note that this may provoke confusion, when the session is reat-
tached on a different terminal, as the value of $TERMCAP cannot be modi-
fied by parent processes.
The "alternate screen" capability is not enabled by default. Set the
altscreen .screenrc command to enable it.
The following is a list of control sequences recognized by screen. (V)
and (A) indicate VT100-specific and ANSI- or ISO-specific functions, re-
spectively.
ESC E Next Line
ESC D Index
ESC M Reverse Index
ESC H Horizontal Tab Set
ESC Z Send VT100 Identification String
ESC 7 (V) Save Cursor and Attributes
ESC 8 (V) Restore Cursor and Attributes
ESC [s (A) Save Cursor and Attributes
ESC [u (A) Restore Cursor and Attributes
ESC c Reset to Initial State
ESC g Visual Bell
ESC Pn p Cursor Visibility (97801)
Pn = 6 Invisible
Pn = 7 Visible
ESC = (V) Application Keypad Mode
ESC > (V) Numeric Keypad Mode
ESC # 8 (V) Fill Screen with E's
ESC \ (A) String Terminator
ESC ^ (A) Privacy Message String (Message Line)
ESC ! Global Message String (Message Line)
ESC k A.k.a. Definition String
ESC P (A) Device Control String. Outputs a string di-
rectly to the host terminal without interpre-
tation.
ESC _ (A) Application Program Command (Hardstatus)
ESC ] 0 ; string ^G (A) Operating System Command (Hardstatus, xterm
title hack)
ESC ] 83 ; cmd ^G (A) Execute screen command. This only works if
multi-user support is compiled into screen.
The pseudo-user :window: is used to check the
access control list. Use addacl :window: -rwx
#? to create a user with no rights and allow
only the needed commands.
Control-N (A) Lock Shift G1 (SO)
Control-O (A) Lock Shift G0 (SI)
ESC n (A) Lock Shift G2
ESC o (A) Lock Shift G3
ESC N (A) Single Shift G2
ESC O (A) Single Shift G3
ESC ( Pcs (A) Designate character set as G0
ESC ) Pcs (A) Designate character set as G1
ESC * Pcs (A) Designate character set as G2
ESC + Pcs (A) Designate character set as G3
ESC [ Pn ; Pn H Direct Cursor Addressing
ESC [ Pn ; Pn f same as above
ESC [ Pn J Erase in Display
Pn = None or 0 From Cursor to End
of Screen
Pn = 1 From Beginning of
Screen to Cursor
Pn = 2 Entire Screen
ESC [ Pn K Erase in Line
Pn = None or 0 From Cursor to End
of Line
Pn = 1 From Beginning of
Line to Cursor
Pn = 2 Entire Line
ESC [ Pn X Erase character
ESC [ Pn A Cursor Up
ESC [ Pn B Cursor Down
ESC [ Pn C Cursor Right
ESC [ Pn D Cursor Left
ESC [ Pn E Cursor next line
ESC [ Pn F Cursor previous line
ESC [ Pn G Cursor horizontal position
ESC [ Pn ` same as above
ESC [ Pn d Cursor vertical position
ESC [ Ps ;...; Ps m Select Graphic Rendition
Ps = None or 0 Default Rendition
Ps = 1 Bold
Ps = 2 (A) Faint
Ps = 3 (A) Standout Mode
(ANSI: Italicized)
Ps = 4 Underlined
Ps = 5 Blinking
Ps = 7 Negative Image
Ps = 22 (A) Normal Intensity
Ps = 23 (A) Standout Mode off
(ANSI: Italicized
off)
Ps = 24 (A) Not Underlined
Ps = 25 (A) Not Blinking
Ps = 27 (A) Positive Image
Ps = 30 (A) Foreground Black
Ps = 31 (A) Foreground Red
Ps = 32 (A) Foreground Green
Ps = 33 (A) Foreground Yellow
Ps = 34 (A) Foreground Blue
Ps = 35 (A) Foreground Magenta
Ps = 36 (A) Foreground Cyan
Ps = 37 (A) Foreground White
Ps = 39 (A) Foreground Default
Ps = 40 (A) Background Black
Ps = ...
Ps = 49 (A) Background Default
ESC [ Pn g Tab Clear
Pn = None or 0 Clear Tab at Cur-
rent Position
Pn = 3 Clear All Tabs
ESC [ Pn ; Pn r (V) Set Scrolling Region
ESC [ Pn I (A) Horizontal Tab
ESC [ Pn Z (A) Backward Tab
ESC [ Pn L (A) Insert Line
ESC [ Pn M (A) Delete Line
ESC [ Pn @ (A) Insert Character
ESC [ Pn P (A) Delete Character
ESC [ Pn S Scroll Scrolling Region Up
ESC [ Pn T Scroll Scrolling Region Down
ESC [ Pn ^ same as above
ESC [ Ps ;...; Ps h Set Mode
ESC [ Ps ;...; Ps l Reset Mode
Ps = 4 (A) Insert Mode
Ps = 20 (A) Automatic Linefeed
Mode
Ps = 34 Normal Cursor Vis-
ibility
Ps = ?1 (V) Application Cursor
Keys
Ps = ?3 (V) Change Terminal
Width to 132
columns
Ps = ?5 (V) Reverse Video
Ps = ?6 (V) Origin Mode
Ps = ?7 (V) Wrap Mode
Ps = ?9 X10 mouse tracking
Ps = ?25 (V) Visible Cursor
Ps = ?47 Alternate Screen
(old xterm code)
Ps = ?1000 (V) VT200 mouse track-
ing
Ps = ?1047 Alternate Screen
(new xterm code)
Ps = ?1049 Alternate Screen
(new xterm code)
ESC [ 5 i (A) Start relay to printer (ANSI Media Copy)
ESC [ 4 i (A) Stop relay to printer (ANSI Media Copy)
ESC [ 8 ; Ph ; Pw t Resize the window to `Ph' lines and `Pw'
columns (SunView special)
ESC [ c Send VT100 Identification String
ESC [ x Send Terminal Parameter Report
ESC [ > c Send VT220 Secondary Device Attributes String
ESC [ 6 n Send Cursor Position Report
INPUT TRANSLATION
In order to do a full VT100 emulation screen has to detect that a se-
quence of characters in the input stream was generated by a keypress on
the user's keyboard and insert the VT100 style escape sequence. Screen
has a very flexible way of doing this by making it possible to map arbi-
trary commands on arbitrary sequences of characters. For standard VT100
emulation the command will always insert a string in the input buffer of
the window (see also command stuff in the command table). Because the
sequences generated by a keypress can change after a reattach from a
different terminal type, it is possible to bind commands to the termcap
name of the keys. Screen will insert the correct binding after each
reattach. See the bindkey command for further details on the syntax and
examples.
Here is the table of the default key bindings. The fourth is what com-
mand is executed if the keyboard is switched into application mode.
┌─────────────────┬──────────────┬──────────┬──────────┐
│ Key name │ Termcap name │ Command │ App mode │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Cursor up │ ku │ \033[A │ \033OA │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Cursor down │ kd │ \033[B │ \033OB │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Cursor right │ kr │ \033[C │ \033OC │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Cursor left │ kl │ \033[D │ \033OD │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 0 │ k0 │ \033[10~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 1 │ k1 │ \033OP │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 2 │ k2 │ \033OQ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 3 │ k3 │ \033OR │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 4 │ k4 │ \033OS │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 5 │ k5 │ \033[15~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 6 │ k6 │ \033[17~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 7 │ k7 │ \033[18~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 8 │ k8 │ \033[19~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 9 │ k9 │ \033[20~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 10 │ k; │ \033[21~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 11 │ F1 │ \033[23~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Function key 12 │ F2 │ \033[24~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Home │ kh │ \033[1~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ End │ kH │ \033[4~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Insert │ kI │ \033[2~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Delete │ kD │ \033[3~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Page up │ kP │ \033[5~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Page down │ kN │ \033[6~ │ │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 0 │ f0 │ 0 │ \033Op │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 1 │ f1 │ 1 │ \033Oq │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 2 │ f2 │ 2 │ \033Or │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 3 │ f3 │ 3 │ \033Os │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 4 │ f4 │ 4 │ \033Ot │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 5 │ f5 │ 5 │ \033Ou │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 6 │ f6 │ 6 │ \033Ov │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 7 │ f7 │ 7 │ \033Ow │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 8 │ f8 │ 8 │ \033Ox │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad 9 │ f9 │ 9 │ \033Oy │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad + │ f+ │ + │ \033Ok │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad - │ f- │ - │ \033Om │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad * │ f* │ * │ \033Oj │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad / │ f/ │ / │ \033Oo │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad = │ fq │ = │ \033OX │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad . │ f. │ . │ \033On │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad , │ f, │ , │ \033Ol │
├─────────────────┼──────────────┼──────────┼──────────┤
│ Keypad enter │ fe │ \015 │ \033OM │
└─────────────────┴──────────────┴──────────┴──────────┘
SPECIAL TERMINAL CAPABILITIES
The following table describes all terminal capabilities that are recog-
nized by screen and are not in the termcap(5) manual. You can place
these capabilities in your termcap entries (in `/etc/termcap') or use
them with the commands `termcap', `terminfo' and `termcapinfo' in your
screenrc files. It is often not possible to place these capabilities in
the terminfo database.
LP (bool) Terminal has VT100 style margins (`magic margins'). Note
that this capability is obsolete because screen uses the
standard 'xn' instead.
Z0 (str) Change width to 132 columns.
Z1 (str) Change width to 80 columns.
WS (str) Resize display. This capability has the desired width and
height as arguments. SunView(tm) example: '\E[8;%d;%dt'.
NF (bool) Terminal doesn't need flow control. Send ^S and ^Q direct
to the application. Same as 'flow off'. The opposite of
this capability is 'nx'.
G0 (bool) Terminal can deal with ISO 2022 font selection sequences.
S0 (str) Switch charset 'G0' to the specified charset. Default is
'\E(%.'.
E0 (str) Switch charset 'G0' back to standard charset. Default is
'\E(B'.
C0 (str) Use the string as a conversion table for font '0'. See the
'ac' capability for more details.
CS (str) Switch cursor-keys to application mode.
CE (str) Switch cursor-keys back to normal mode.
AN (bool) Turn on autonuke. See the 'autonuke' command for more de-
tails.
OL (num) Set the output buffer limit. See the 'obuflimit' command
for more details.
KJ (str) Set the encoding of the terminal. See the 'encoding' com-
mand for valid encodings.
AF (str) Change character foreground color in an ANSI conform way.
This capability will almost always be set to '\E[3%dm'
('\E[3%p1%dm' on terminfo machines).
AB (str) Same as 'AF', but change background color.
AX (bool) Does understand ANSI set default fg/bg color (\E[39m /
\E[49m).
XC (str) Describe a translation of characters to strings depending
on the current font. More details follow in the next sec-
tion.
XT (bool) Terminal understands special xterm sequences (OSC, mouse
tracking).
C8 (bool) Terminal needs bold to display high-intensity colors (e.g.
Eterm).
TF (bool) Add missing capabilities to the termcap/info entry. (Set by
default).
CHARACTER TRANSLATION
Screen has a powerful mechanism to translate characters to arbitrary
strings depending on the current font and terminal type. Use this fea-
ture if you want to work with a common standard character set (say
ISO8851-latin1) even on terminals that scatter the more unusual charac-
ters over several national language font pages.
Syntax:
XC=<charset-mapping>{,,<charset-mapping>}
<charset-mapping> := <designator><template>{,<mapping>}
<mapping> := <char-to-be-mapped><template-arg>
The things in braces may be repeated any number of times.
A <charset-mapping> tells screen how to map characters in font <designa-
tor> ('B': Ascii, 'A': UK, 'K': German, etc.) to strings. Every <map-
ping> describes to what string a single character will be translated. A
template mechanism is used, as most of the time the codes have a lot in
common (for example strings to switch to and from another charset). Each
occurrence of '%' in <template> gets substituted with the <template-arg>
specified together with the character. If your strings are not similar
at all, then use '%' as a template and place the full string in <tem-
plate-arg>. A quoting mechanism was added to make it possible to use a
real '%'. The '\' character quotes the special characters '\', '%', and
','.
Here is an example:
termcap hp700 'XC=B\E(K%\E(B,\304[,\326\\\\,\334]'
This tells screen how to translate ISOlatin1 (charset 'B') upper case
umlaut characters on a hp700 terminal that has a German charset. '\304'
gets translated to '\E(K[\E(B' and so on. Note that this line gets
parsed *three* times before the internal lookup table is built, there-
fore a lot of quoting is needed to create a single '\'.
Another extension was added to allow more emulation: If a mapping trans-
lates the unquoted '%' char, it will be sent to the terminal whenever
screen switches to the corresponding <designator>. In this special case
the template is assumed to be just '%' because the charset switch se-
quence and the character mappings normally haven't much in common.
This example shows one use of the extension:
termcap xterm 'XC=K%,%\E(B,[\304,\\\\\326,]\334'
Here, a part of the German ('K') charset is emulated on an xterm. If
screen has to change to the 'K' charset, '\E(B' will be sent to the ter-
minal, i.e. the ASCII charset is used instead. The template is just '%',
so the mapping is straightforward: '[' to '\304', '\' to '\326', and ']'
to '\334'.
ENVIRONMENT
COLUMNS Number of columns on the terminal (overrides termcap en-
try).
HOME Directory in which to look for .screenrc.
LINES Number of lines on the terminal (overrides termcap en-
try).
LOCKPRG Screen lock program.
NETHACKOPTIONS Turns on nethack option.
PATH Used for locating programs to run.
SCREENCAP For customizing a terminal's TERMCAP value.
SCREENDIR Alternate socket directory.
SCREENRC Alternate user screenrc file.
SHELL Default shell program for opening windows (default
/bin/sh). See also shell .screenrc command.
STY Alternate socket name.
SYSSCREENRC Alternate system screenrc file.
TERM Terminal name.
TERMCAP Terminal description.
WINDOW Window number of a window (at creation time).
FILES
.../screen-4.?.??/etc/screenrc
.../screen-4.?.??/etc/etcscreenrc Examples in the screen distribution
package for private and global ini-
tialization files.
$SYSSCREENRC
/etc/screenrc screen initialization commands
$SCREENRC
$HOME/.screenrc Read in after /etc/screenrc
$SCREENDIR/S-<login>
/run/screen/S-<login> Socket directories (default)
/usr/tmp/screens/S-<login> Alternate socket directories.
<socket directory>/.termcap Written by the "termcap" output func-
tion
/usr/tmp/screens/screen-exchange or
/tmp/screen-exchange screen `interprocess communication
buffer'
hardcopy.[0-9] Screen images created by the hardcopy
function
screenlog.[0-9] Output log files created by the log
function
/usr/lib/terminfo/?/* or
/etc/termcap Terminal capability databases
/run/utmp Login records
$LOCKPRG Program that locks a terminal.
AUTHORS
Originally created by Oliver Laumann. For a long time maintained and de-
veloped by Juergen Weigert, Michael Schroeder, Micah Cowan and Sadrul
Habib Chowdhury. Since 2015 maintained and developed by Amadeusz Slawin-
ski <amade@asmblr.net> and Alexander Naumov <alexander_naumov@open-
suse.org>.
COPYLEFT
Copyright (c) 2018-2023
Alexander Naumov <alexander_naumov@opensuse.org>
Amadeusz Slawinski <amade@asmblr.net>
Copyright (c) 2015-2017
Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
Alexander Naumov <alexander_naumov@opensuse.org>
Amadeusz Slawinski <amade@asmblr.net>
Copyright (c) 2010-2015
Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
Sadrul Habib Chowdhury <sadrul@users.sourceforge.net>
Copyright (c) 2008, 2009
Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
Micah Cowan <micah@cowan.name>
Sadrul Habib Chowdhury <sadrul@users.sourceforge.net>
Copyright (C) 1993-2003
Juergen Weigert <jnweiger@immd4.informatik.uni-erlangen.de>
Michael Schroeder <mlschroe@immd4.informatik.uni-erlangen.de>
Copyright (C) 1987 Oliver Laumann
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABIL-
ITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public Li-
cense for more details.
You should have received a copy of the GNU General Public License along
with this program (see the file COPYING); if not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA
CONTRIBUTORS
Vincent Lefevre <vincent@vinc17.net>,
Carl Drougge <bearded@longhaired.org>,
Maarten ter Huurne <maarten@treewalker.org>,
Jussi Kukkonen <jussi.kukkonen@intel.com>,
Eric S. Raymond <esr@thyrsus.com>,
Thomas Renninger <treen@suse.com>,
Axel Beckert <abe@deuxchevaux.org>,
Ken Beal <kbeal@amber.ssd.csd.harris.com>,
Rudolf Koenig <rfkoenig@immd4.informatik.uni-erlangen.de>,
Toerless Eckert <eckert@immd4.informatik.uni-erlangen.de>,
Wayne Davison <davison@borland.com>,
Patrick Wolfe <pat@kai.com, kailand!pat>,
Bart Schaefer <schaefer@cse.ogi.edu>,
Nathan Glasser <nathan@brokaw.lcs.mit.edu>,
Larry W. Virden <lvirden@cas.org>,
Howard Chu <hyc@hanauma.jpl.nasa.gov>,
Tim MacKenzie <tym@dibbler.cs.monash.edu.au>,
Markku Jarvinen <mta@{cc,cs,ee}.tut.fi>,
Marc Boucher <marc@CAM.ORG>,
Doug Siebert <dsiebert@isca.uiowa.edu>,
Ken Stillson <stillson@tsfsrv.mitre.org>,
Ian Frechett <frechett@spot.Colorado.EDU>,
Brian Koehmstedt <bpk@gnu.ai.mit.edu>,
Don Smith <djs6015@ultb.isc.rit.edu>,
Frank van der Linden <vdlinden@fwi.uva.nl>,
Martin Schweikert <schweik@cpp.ob.open.de>,
David Vrona <dave@sashimi.lcu.com>,
E. Tye McQueen <tye%spillman.UUCP@uunet.uu.net>,
Matthew Green <mrg@eterna.com.au>,
Christopher Williams <cgw@pobox.com>,
Matt Mosley <mattm@access.digex.net>,
Gregory Neil Shapiro <gshapiro@wpi.WPI.EDU>,
Johannes Zellner <johannes@zellner.org>,
Pablo Averbuj <pablo@averbuj.com>.
AVAILABILITY
The latest official release of screen available via anonymous ftp from
ftp.gnu.org/gnu/screen/ or any other GNU distribution site. The home
page of screen is https://savannah.gnu.org/projects/screen/ and the git
repo is https://git.savannah.gnu.org/cgit/screen.git. If you want to
help, send a note to screen-devel@gnu.org.
BUGS
• `dm' (delete mode) and `xs' are not handled correctly (they are ig-
nored). `xn' is treated as a magic-margin indicator.
• Screen has no clue about double-high or double-wide characters. But
this is the only area where vttest is allowed to fail.
• It is not possible to change the environment variable $TERMCAP when
reattaching under a different terminal type.
• The support of terminfo based systems is very limited. Adding extra
capabilities to $TERMCAP may not have any effects.
• Screen does not make use of hardware tabs.
• Screen must be installed as set-uid with owner root on most systems
in order to be able to correctly change the owner of the tty device
file for each window. Special permission may also be required to
write the file /run/utmp.
• Entries in /run/utmp are not removed when screen is killed with
SIGKILL. This will cause some programs (like "w" or "rwho") to ad-
vertise that a user is logged on who really isn't.
• Screen may give a strange warning when your tty has no utmp entry.
• When the modem line was hung up, screen may not automatically detach
(or quit) unless the device driver is configured to send a HANGUP
signal. To detach a screen session use the -D or -d command line op-
tion.
• If a password is set, the command line options -d and -D still detach
a session without asking.
• Both breaktype and defbreaktype change the break generating method
used by all terminal devices. The first should change a window spe-
cific setting, where the latter should change only the default for
new windows.
• When attaching to a multiuser session, the user's .screenrc file is
not sourced. Each user's personal settings have to be included in the
.screenrc file from which the session is booted, or have to be
changed manually.
• A weird imagination is most useful to gain full advantage of all the
features.
Send bug-reports, fixes, enhancements, t-shirts, money, beer & pizza to
screen-devel@gnu.org.
SEE ALSO
termcap(5), utmp(5), vi(1), captoinfo(1), tic(1), tty(4), pty(7)
GNU Screen 4.9.1 2023 Aug 20 SCREEN(1)
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