SYSTEMD-SOCKET-ACTIVATE(1) systemd-socket-activate SYSTEMD-SOCKET-ACTIVATE(1)
NAME
systemd-socket-activate - Test socket activation of daemons
SYNOPSIS
systemd-socket-activate [OPTIONS...] daemon [OPTIONS...]
DESCRIPTION
systemd-socket-activate may be used to launch a socket-activated service
program from the command line for testing purposes. It may also be used
to launch individual instances of the service program per connection.
The daemon to launch and its options should be specified after options
intended for systemd-socket-activate.
If the --inetd option is given, the socket file descriptor will be used
as the standard input and output of the launched process. Otherwise,
standard input and output will be inherited, and sockets will be passed
through file descriptors 3 and higher. Sockets passed through
$LISTEN_FDS to systemd-socket-activate will be passed through to the
daemon, in the original positions. Other sockets specified with
--listen= will use consecutive descriptors. By default,
systemd-socket-activate listens on a stream socket, use --datagram and
--seqpacket to listen on datagram or sequential packet sockets instead
(see below).
OPTIONS
-l address, --listen=address
Listen on this address. Takes a string like "2000" or
"127.0.0.1:2001".
Added in version 230.
-a, --accept
Launch an instance of the service program for each connection and
pass the connection socket.
Added in version 230.
-d, --datagram
Listen on a datagram socket (SOCK_DGRAM), instead of a stream socket
(SOCK_STREAM). May not be combined with --seqpacket.
Added in version 230.
--seqpacket
Listen on a sequential packet socket (SOCK_SEQPACKET), instead of a
stream socket (SOCK_STREAM). May not be combined with --datagram.
Added in version 230.
--inetd
Use the inetd protocol for passing file descriptors, i.e. as
standard input and standard output, instead of the new-style
protocol for passing file descriptors using $LISTEN_FDS (see above).
Added in version 230.
-E VAR[=VALUE], --setenv=VAR[=VALUE]
Add this variable to the environment of the launched process. If VAR
is followed by "=", assume that it is a variable–value pair.
Otherwise, obtain the value from the environment of
systemd-socket-activate itself.
Added in version 230.
--fdname=NAME[:NAME...]
Specify names for the file descriptors passed. This is equivalent to
setting FileDescriptorName= in socket unit files, and enables use of
sd_listen_fds_with_names(3). Multiple entries may be specifies using
separate options or by separating names with colons (":") in one
option. In case more names are given than descriptors, superfluous
ones will be ignored. In case less names are given than descriptors,
the remaining file descriptors will be unnamed.
Added in version 230.
-h, --help
Print a short help text and exit.
--version
Print a short version string and exit.
ENVIRONMENT VARIABLES
$LISTEN_FDS, $LISTEN_PID, $LISTEN_FDNAMES
See sd_listen_fds(3).
Added in version 230.
$SYSTEMD_LOG_TARGET, $SYSTEMD_LOG_LEVEL, $SYSTEMD_LOG_TIME,
$SYSTEMD_LOG_COLOR, $SYSTEMD_LOG_LOCATION
Same as in systemd(1).
Added in version 230.
EXAMPLES
Example 1. Run an echo server on port 2000
$ systemd-socket-activate -l 2000 --inetd -a cat
Example 2. Run a socket-activated instance of systemd-journal-
gatewayd(8)
$ systemd-socket-activate -l 19531 /usr/lib/systemd/systemd-journal-gatewayd
SEE ALSO
systemd(1), systemd.socket(5), systemd.service(5), systemd-run(1),
sd_listen_fds(3), sd_listen_fds_with_names(3), cat(1)
systemd 257.9 SYSTEMD-SOCKET-ACTIVATE(1)
Generated by dwww version 1.16 on Tue Dec 16 05:04:57 CET 2025.