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).
-l address, --listen=address
Listen on this address. Takes a string like "2000" or
Launch an instance of the service program for each connection
and pass the connection socket.
Listen on a datagram socket (SOCK_DGRAM), instead of a stream
socket (SOCK_STREAM). May not be combined with --seqpacket.
Listen on a sequential packet socket (SOCK_SEQPACKET),
instead of a stream socket (SOCK_STREAM). May not be combined
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
-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
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.
Print a short help text and exit.
Print a short version string and exit.
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
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have
a bug report for this manual page, see
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2021-08-27. (At that
time, the date of the most recent commit that was found in the
repository was 2021-08-27.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
systemd 249 SYSTEMD-SOCKET-ACTIVATE(1)