PV(1) User Commands PV(1)
NAME
pv - monitor the progress of data through a pipe
SYNOPSIS
pv [OPTION]... [FILE]...
pv -d|--watchfd PID[:FD] [OPTION]...
pv -R|--remote PID [OPTION]...
DESCRIPTION
Show the progress of data through a pipeline by giving information such
as time elapsed, percentage completed (with progress bar), current
throughput rate, total data transferred, and ETA.
Each FILE is copied to standard output. With no FILE, or when FILE is
“-”, standard input is read. This is the same behaviour as cat(1).
OPTIONS
Display switches
If no display switches are specified, pv behaves as if “--progress”,
“--timer”, “--eta”, “--rate”, and “--bytes” had been given. Otherwise,
only those display types that are explicitly switched on will be shown.
-p, --progress
Turn the progress bar on. If any inputs are not files, or are
unreadable, and no size was explicitly given with “--size”, the
progress bar cannot indicate how close to completion the transfer
is, so it will just move left and right to indicate that data is
moving - or, with “--gauge”, the bar will indicate the current
rate as a percentage of the maximum rate seen so far.
-t, --timer
Turn the timer on. This will display the total elapsed time that
pv has been running for.
-e, --eta
Turn the ETA countdown on. This will estimate, based on current
transfer rates and the total data size, how long it will be be-
fore completion. The countdown is prefixed with “ETA”. This op-
tion will have no effect if the total data size cannot be deter-
mined.
-I, --fineta
Turn the ETA countdown on, but display the estimated local time
at which the transfer will finish, instead of the amount of time
remaining. When the estimated time is more than 6 hours in the
future, the date is shown as well. The time is prefixed with
“FIN” for finish time. As with “--eta”, this option will have no
effect if the total data size cannot be determined.
-r, --rate
Turn the rate counter on. This will display the current rate of
data transfer. The rate is shown in square brackets “[]”.
-a, --average-rate
Turn the average rate counter on. This will display the current
average rate of data transfer, over the last 30 seconds by de-
fault (see “--average-rate-window”). The average rate is shown
in brackets “()”.
-b, --bytes
Turn the total byte counter on. This will display the total
amount of data transferred so far.
-T, --buffer-percent
Turn on the transfer buffer percentage display. This will show
the percentage of the transfer buffer in use. Implies
“--no-splice”. The transfer buffer percentage is shown in curly
brackets “{}”.
-A NUM, --last-written NUM
Show the last NUM bytes written. Implies “--no-splice”.
-F FORMAT, --format FORMAT
Ignore all of the above options and instead use the format string
FORMAT to determine the output format. See the FORMATTING sec-
tion below.
-n, --numeric
Numeric output. Instead of giving a visual indication of
progress, write an integer percentage, one per line, on standard
error, suitable for passing to a tool such as dialog(1). Note
that “--force” is not required if “--numeric” is being used.
Combining “--numeric” with “--bytes” will cause the number of
bytes processed so far to be output instead of a percentage.
Adding “--line-mode” as well as “--bytes” writes the number of
lines instead of bytes or a percentage. Adding “--rate” adds the
transfer rate to each output line (if “--bytes” is also in use,
the rate comes after the byte/line count). Adding “--timer” pre-
fixes each output line with the elapsed time so far, as a decimal
number of seconds.
Combining “--numeric” with “--format” allows for custom output.
The default format string components for “--numeric” are
“%t %b %r %{progress-amount-only}” in that order, each item being
active or inactive according to the rules above (so the default
with no other options is “%{progress-amount-only}”.
-q, --quiet
No output. Useful if the “--rate-limit” option is being used on
its own to limit the transfer rate of a pipe.
Output modifiers
-8, --bits
Use bits instead of bytes for the byte and rate counters. The
output suffix will be “b” instead of “B”.
-k, --si
Display and interpret suffixes as multiples of 1000 rather than
the default of 1024. Note that this only takes effect on options
after this one, so for consistency, specify this option first.
-W, --wait
Wait until the first byte has been transferred before showing any
progress information or calculating any ETAs. Useful if the pro-
gram you are piping to or from requires extra information before
it starts, such as when piping data into gpg(1) or mcrypt(1)
which require a passphrase before data can be processed.
-D SEC, --delay-start SEC
Wait until SEC seconds have passed before showing any progress
information, for example in a script where you only want to show
a progress bar if it starts taking a long time. The value of SEC
can be a decimal such as “0.5”.
-s SIZE, --size SIZE
Assume the total amount of data to be transferred is SIZE bytes
when calculating percentages and ETAs. A suffix of “K”, “M”,
“G”, or “T” can be added to denote kibibytes (*1024), mebibytes,
gibibytes, tebibytes. If “--si” appears before this option, suf-
fixes will denote kilobytes (*1000), megabytes, and so on in-
stead.
If SIZE starts with “@”, the size of file whose name follows the
@ will be used.
-g, --gauge
If the progress bar is shown but the size is not known, then in-
stead of moving the bar left and right to show progress, show the
current transfer rate as a percentage of the maximum rate seen so
far.
-l, --line-mode
Instead of counting bytes, count lines (newline characters). The
progress bar will only move when a new line is found, and the
value passed to “--size” will be interpreted as a line count.
If this option is used without “--size”, the "total size" (in
this case, total line count) is calculated by reading through all
input files once before transfer starts. If any inputs are pipes
or non-regular files, or are unreadable, the total size will not
be calculated.
-0, --null
Count lines as terminated with a null byte instead of with a new-
line. This option implies “--line-mode”.
-i SEC, --interval SEC
Wait SEC seconds between updates. The default is to update every
second. The value of SEC can be a decimal such as “0.1”.
-m SEC, --average-rate-window SEC
Compute current average rate over a SEC seconds window for aver-
age rate and ETA calculations. The default is 30 seconds. The
value must be an integer.
-w WIDTH, --width WIDTH
Assume the terminal is WIDTH columns wide, instead of trying to
work it out (or assuming 80 if it cannot be guessed). If this
option is used, the output width will not be adjusted if the
width of the terminal changes while the transfer is running.
-H HEIGHT, --height HEIGHT
Assume the terminal is HEIGHT rows high, instead of trying to
work it out (or assuming 25 if it cannot be guessed). If this
option is used, the output height will not be adjusted if the
height of the terminal changes while the transfer is running.
-N NAME, --name NAME
Prefix the output information with NAME. Useful in conjunction
with “--cursor” if you have a complicated pipeline and you want
to be able to tell different parts of it apart.
-u STYLE, --bar-style STYLE
Change the default progress bar style shown by “--progress”, or
by the “--format” sequences “%{progress}” or
“%{progress-bar-only}”, to STYLE. The STYLE can be one of plain
(the default), block, granular, or shaded. These styles are de-
scribed in the FORMATTING section below.
-x SPEC, --extra-display SPEC
As well as displaying progress to the terminal, also write it to
SPEC. The SPEC must start with a comma-separated list of desti-
nations, and can optionally be followed by a colon and a format
string. The destinations can be windowtitle or window for the
xterm window title, and processtitle, proctitle, process, or proc
for the process title displayed by ps(1). If a format string is
not supplied, the same format is used as for the terminal. For
example, “-x 'window,process:%t %b %r'” will show the elapsed
time, bytes transferred, and rate, in both the window title and
the process title.
-v, --stats
At the end of the transfer, write an additional line showing the
transfer rate minimum, maximum, mean, and standard deviation.
The values are always in bytes per second (or bits, with
“--bits”).
-f, --force
Force output. Normally, pv will not output any visual display if
standard error is not a terminal. This option forces it to do
so.
-c, --cursor
Use cursor positioning escape sequences instead of just using
carriage returns. This is useful in conjunction with “--name” if
you are using multiple pv invocations in a single pipeline.
Data transfer modifiers
-o FILE, --output FILE
Write data to FILE instead of standard output. If the file al-
ready exists, it will be truncated.
-L RATE, --rate-limit RATE
Limit the transfer to a maximum of RATE bytes per second. The
same suffixes as “--size” can be used.
-B BYTES, --buffer-size BYTES
Use a transfer buffer size of BYTES bytes. The same suffixes as
“--size” can be used. The default buffer size is the block size
of the input file's filesystem multiplied by 32 (512KiB max), or
400KiB if the block size cannot be determined. This can be use-
ful on platforms like macOS with pipelines that perform better
with specific buffer sizes such as 1024. Implies “--no-splice”.
-C, --no-splice
Never use splice(2), even if it would normally be possible. The
splice(2) system call is a more efficient way of transferring
data from or to a pipe than regular read(2) and write(2), but
means that the transfer buffer may not be used. This prevents
“--buffer-percent” and “--last-written” from working, cannot work
with “--discard”, and makes “--buffer-size” redundant, so using
any of those options automatically switches on “--no-splice”.
Switching on this option results in a small loss of transfer ef-
ficiency. It has no effect on systems where splice(2) is un-
available.
-E, --skip-errors
Ignore read errors by attempting to skip past the offending sec-
tions. The corresponding parts of the output will be null bytes.
At first only a few bytes will be skipped, but if there are many
errors in a row then the skips will move up to chunks of 512.
This is intended to be similar to “dd conv=sync,noerror”.
Specify “--skip-errors” twice to only report a read error once
per file, instead of reporting each byte range skipped.
-Z BYTES, --error-skip-block BYTES
When ignoring read errors with “--skip-errors”, instead of trying
to adaptively skip by reading small amounts and skipping progres-
sively larger sections until a read succeeds, move to the next
file block of BYTES bytes as soon as an error occurs. There may
still be some shorter skips where the block being skipped coin-
cides with the end of the transfer buffer. The same suffixes as
“--size” can be used.
This option can only be used with “--skip-errors” and is intended
for use when reading from a block device, such as “--skip-er-
rors --error-skip-block 4K” to skip in 4 kibibyte blocks. This
will speed up reads from faulty media, at the expense of poten-
tially losing more data.
-S, --stop-at-size
If a size was specified with “--size”, stop transferring data
once that many bytes have been written, instead of continuing to
the end of input.
-Y, --sync
After every write operation, synchronise the buffer caches to
disk with fdatasync(2). This has no effect when the output is a
pipe. Using “--sync” may improve the accuracy of the progress
bar when writing to a slow disk.
-K, --direct-io
Set the O_DIRECT flag on all inputs and outputs, if it is avail-
able. This will minimise the effect of caches, at the cost of
performance. Due to memory alignment requirements, it also may
cause read or write failures with an error of “Invalid argument”,
especially if reading and writing files across a variety of
filesystems in a single pv call. Use this option with caution.
-X, --discard
Instead of transferring input data to standard output, discard
it. This is equivalent to redirecting standard output to
/dev/null, except that write(2) is never called. Implies
“--no-splice”.
-U FILE, --store-and-forward FILE
Instead of passing data through immediately, do it in two stages
- first read all input and write it to FILE, and then once the
input is exhausted, read all of FILE and write it to the output.
FILE remains in place afterwards, unless it is “-”, in which case
pv creates a temporary file for this purpose, and automatically
removes it afterwards.
This can be useful if you have a pipeline which generates data
(your input) quickly but you don't know the size, and you wish to
pass it to some slower process, once all of the input has been
generated and you know its size, so you can see its progress.
Note that when doing this with relatively small amounts of data,
“--no-splice” may be preferable so that pipe buffering doesn't
affect the progress display.
Alternative operating modes
-d PID[:FD], --watchfd PID[:FD]
Instead of transferring data, watch file descriptor FD of process
PID, and show its progress. The pv process will exit when FD ei-
ther changes to a different file, changes read/write mode, or is
closed; other data transfer modifiers - and remote control - may
not be used with this option.
If only a PID is specified, then that process will be watched,
and all regular files and block devices it opens will be shown
with a progress bar. The pv process will exit when process PID
exits.
-R PID, --remote PID
Remotely control another instance of pv with process ID PID, mak-
ing it act as though it had been given this instance's command
line. For example, if “pv --rate-limit 123K” is running with
process ID 9876, then running “pv --re-
mote 9876 --rate-limit 321K” will cause process 9876 to start us-
ing a rate limit of 321KiB instead of 123KiB. Note that some op-
tions cannot be changed while running, such as “--cursor”,
“--line-mode”, “--force”, “--delay-start”, “--skip-errors”, and
“--stop-at-size”.
Other options
-P FILE, --pidfile FILE
Save the process ID of pv in FILE. The file will be replaced if
it already exists, and will be removed when pv exits. While pv
is running, FILE will contain a single number - the process ID of
pv - followed by a newline.
-h, --help
Print a usage message on standard output and exit successfully.
-V, --version
Print version information on standard output and exit success-
fully.
FORMATTING
Format strings used by “--format” and “--extra-display” can contain the
following sequences:
%p, %{progress}
Progress bar (suffixed with a percentage if the size is known).
Equivalent to “--progress”. Expands to fill the remaining space
unless prefixed by a number to set the width, such as “%20p” or
“%20{progress}”.
%{progress-bar-only}
Progress bar, without any sides, and without any percentage dis-
played afterwards. Expands to fill the remaining space unless
prefixed by a number.
%{progress-amount-only}
The percentage completion (or maximum rate, with “--gauge” when
the size is unknown).
%{bar-plain}
Progress bar in the standard plain format, without any sides, and
without any percentage displayed afterwards. Expands to fill the
remaining space unless prefixed by a number.
%{bar-block}
Progress bar using Unicode full blocks, without any sides, and
without any percentage displayed afterwards. Expands to fill the
remaining space unless prefixed by a number. If UTF-8 output is
not available, the plain format is used.
%{bar-granular}
Progress bar using Unicode full blocks, and 1/8th blocks for par-
tial fills, providing a more granular display. Like the other
“%{bar}” strings this shows the bar without any sides, and with-
out any percentage displayed afterwards, and expands to fill the
remaining space unless prefixed by a number. If UTF-8 output is
not available, the plain format is used.
%{bar-shaded}
Progress bar using Unicode full blocks and shade characters -
dark and medium shade are used for partial fills, and the light
shade is used for the background. Like the other “%{bar}”
strings this shows the bar without any sides, and without any
percentage displayed afterwards, and expands to fill the remain-
ing space unless prefixed by a number. If UTF-8 output is not
available, the plain format is used.
%t, %{timer}
Elapsed time. Equivalent to “--timer”.
%e, %{eta}
ETA as time remaining. Equivalent to “--eta”.
%I, %{fineta}
ETA as local time at which the transfer will finish. Equivalent
to “--fineta”.
%r, %{rate}
Current data transfer rate. Equivalent to “--rate”.
%a, %{average-rate}
Average data transfer rate. Equivalent to “--average-rate”.
%b, %{bytes}, %{transferred}
Bytes transferred so far (or lines if “--line-mode” was speci-
fied). Equivalent to “--bytes”. If “--bits” was specified, “%b”
shows the bits transferred so far, not bytes.
%T, %{buffer-percent}
Percentage of the transfer buffer in use. Equivalent to
“--buffer-percent”. Displays “{----}” if the transfer is being
done with splice(2), since splicing to or from pipes does not use
the buffer.
%nA, %n{last-written}
Show the last n bytes written (for example, “%16A” shows the last
16 bytes). Shows only dots if the transfer is being done with
splice(2), since splicing to or from pipes does not use the
buffer.
%nL, %n{previous-line}
Show the first n bytes of the most recently written line (for ex-
ample, “%40L” shows the first 40 bytes). If no n is given, then
this expands to fill the available space. Shows only spaces if
the transfer is being done with splice(2).
%N, %{name}
Show the name prefix given by “--name”. Padded to 9 characters
with spaces, and suffixed with “:”.
%{sgr:colour,...}
Emit ECMA-48 SGR (Select Graphic Rendition) codes if the terminal
supports colours, where colour,... is a comma-separated list of
any of the keywords below, or the numeric values from con-
sole_codes(4). If colour support is not available, nothing is
emitted.
Supported keywords are: reset or none, black, red, green, brown
or yellow, blue, magenta, cyan, white, fg-black, fg-red,
fg-green, fg-brown or fg-yellow, fg-blue, fg-magenta, fg-cyan,
fg-white, fg-default, bg-black, bg-red, bg-green, bg-brown or
bg-yellow, bg-blue, bg-magenta, bg-cyan, bg-white, bg-default,
bold, dim, italic, underscore or underline, blink, reverse,
no-bold or no-dim, no-italic, no-underscore or no-underline,
no-blink, no-reverse.
With colours, the optional "fg-" prefix indicates foreground; a
prefix of "bg-" indicates background.
For example, “%{sgr:green,bold}TEXT%{sgr:reset}“ will make TEXT
bold green on supported terminals.
%% A single “%”.
Any other contents are reproduced in the progress display as-is.
The format string equivalent of the default display switches is
“%b %t %r %p %e”.
EXAMPLES
Some suggested common switch combinations:
pv -ptebar
Show a progress bar, elapsed time, estimated completion time,
byte counter, average rate, and current rate.
pv -betlap
Show a progress bar, elapsed time, estimated completion time,
line counter, and average rate, counting lines instead of bytes.
pv -btrpg
Show the amount transferred, elapsed time, current rate, and a
gauge showing the current rate as a percentage of the maximum
rate seen - useful in a pipeline where the total size is unknown.
(If the size is known, these options will show the percentage
completion instead of the rate gauge).
pv -t Show only the elapsed time - useful as a simple timer, such as
“sleep 10m | pv -t”.
pv -pterb
The default behaviour: progress bar, elapsed time, estimated com-
pletion time, current rate, and byte counter.
On macOS, it may be useful to specify “--buffer-size 1024” in a
pipeline, as this may improve performance.
To watch how quickly a file is transferred using nc(1):
pv file | nc -w 1 somewhere.com 3000
A similar example, transferring a file from another process and passing
the expected size to pv:
cat file | pv --size 12345 | nc -w 1 somewhere.com 3000
To watch the progress of creating a tar.gz archive:
tar cf - directory/ \
| pv --size $(du -sb directory/ | awk '{print $1}') \
| gzip -9 \
> out.tar.gz
Taking an image of a disk, skipping errors:
pv -EE /dev/your/disk/device > disk-image.img
Writing an image back to a disk:
pv disk-image.img > /dev/your/disk/device
Zeroing a disk:
pv < /dev/zero > /dev/your/disk/device
Note that if the input size cannot be calculated, and the output is a
block device, then the size of the block device will be used and pv will
automatically stop at that size as if “--stop-at-size” had been given.
(Linux and macOS only): Watching file descriptor 3 opened by another
process 1234:
pv --watchfd 1234:3
(Linux and macOS only): Watching all file descriptors used by process
1234:
pv --watchfd 1234
Rate-limiting the transfer between two processes in a pipeline, with no
display:
producer | pv --quiet --rate-limit 1M | consumer
Sending logs to a processing script, showing the most recent line as
part of the progress display:
pv --format '%a %p : %L' big.log | processing-script
Showing progress as lines of JSON data:
pv --numeric --format '{"elapsed":%t,"bytes":%b,"rate":%r,"percentage":%{progress-amount-only}}' big.log | processing-script
EXIT STATUS
An exit status of 1 indicates a problem with the “--remote” or “--pid-
file” options.
Any other exit status is a bitmask of the following:
2 One or more files could not be accessed, stat(2)ed, or opened.
4 An input file was the same as the output file.
8 Internal error with closing a file or moving to the next file.
16 There was an error while transferring data from one or more input
files.
32 A signal was caught that caused an early exit.
64 Memory allocation failed.
A zero exit status indicates no problems.
ENVIRONMENT
The following environment variables may affect pv:
HOME The current user's home directory. This may be used by “--re-
mote” to exchange messages between pv instances: if the
/run/user/UID/ directory does not exist (where UID is the current
user ID), then $HOME/.pv/ will be used instead.
TMPDIR, TMP
The directory to create per-tty lock files for the terminal when
using “--cursor”. If TMPDIR is set to a non-empty value, it is
the directory under which lock files are created. Otherwise, TMP
is used. If neither are set, then /tmp is used.
NOTES
In some versions of bash(1) and zsh(1), the construct “<(pv filename)”
will not output any progress to the terminal when run from an interac-
tive shell, due to the subprocess being run in a separate process group
from the one that owns the terminal. In these cases, use “--force”.
If pv is used in a pipeline in zsh version 5.8, and the last command in
the pipeline is based on shell builtins, zsh takes control of the termi-
nal away from pv, preventing progress from being displayed. For exam-
ple, this will produce no progress bar:
pv InputFile | { while read -r line; do sleep 0.1; done; }
To work around this, put the last commands of the pipeline in normal
brackets to force the use of a subshell:
pv InputFile | ( while read -r line; do sleep 0.1; done; )
Refer to ]8;;https://codeberg.org/a-j-wood/pv/issues/105\issue #105]8;;\ for full details.
The “--remote” option requires that either /run/user/<uid>/ or $HOME/
can be written to, for inter-process communication.
The “--size” option has no effect if used with “--watchfd PID” to watch
all file descriptors of a process, but will work with “--watchfd PID:FD”
to watch a single file descriptor.
If the input size cannot be calculated, and the output is a block de-
vice, then pv will read the output device's size, use that as if it had
been passed to “--size”, and activate “--stop-at-size”.
The “%nA” and “%nL” format sequences may not be effective with small in-
put files, and “%nL” may be a few lines out due to buffering within the
pipeline itself.
Numbers passed to “--size”, “--rate-limit”, “--buffer-size”, and “--er-
ror-skip-block” may all be expressed as decimals if followed by a suf-
fix, so for example “--size 1.5G” is equivalent to “--size 1536M”.
Numbers passed to “--interval” and “--delay-start” may be integers or
decimals, but may not have a suffix.
Numbers passed to “--last-written”, “--width”, “--height”, “--aver-
age-rate-window”, and “--remote” must be integers with no suffix.
REPORTING BUGS
Please report any bugs to pv@ivarch.com.
Alternatively, use the issue tracker linked from the ]8;;https://www.ivarch.com/programs/pv.shtml\pv home page]8;;\.
SEE ALSO
cat(1), splice(2), fdatasync(2), open(2) (for O_DIRECT), con-
sole_codes(4)
COPYRIGHT
Copyright © 2002-2008, 2010, 2012-2015, 2017, 2021, 2023-2025 Andrew
Wood.
License GPLv3+: ]8;;https://www.gnu.org/licenses/gpl-3.0.html\GNU GPL version 3 or later]8;;\.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Please see the package's ACKNOWLEDGEMENTS file for a complete list of
contributors.
pv-1.9.31 2025-01-28 PV(1)
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