systemd-activate man page

systemd-activate — Test socket activation of daemons


/usr/lib/systemd/systemd-activate [Options...] daemon [Options...]


systemd-activate can be used to launch a socket activated daemon from the command line for testing purposes. It can also be used to launch single instances of the daemon per connection (inetd-style).

The daemon to launch and its options should be specified after options intended for systemd-activate.

If the -a option is given, file descriptor of the connection 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-activate will be passed through to the daemon, in the original positions. Other sockets specified with --listen will use consecutive descriptors.


-l address, --listen=address
Listen on this address. Takes a string like 2000 or
-a, --accept
Launch a separate instance of daemon per connection and pass the connection socket as standard input and standard output.
-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-activate itself.
-h, --help
Print a short help text and exit.
Print a short version string and exit.

Environment variables

See sd_listen_fds(3).
Same as in systemd(1).


Example 1. Run an echo server on port 2000

$ /usr/lib/systemd/systemd-activate -l 2000 -a cat

Example 2. Run a socket activated instance of systemd-journal-gatewayd(8)

$ /usr/lib/systemd/systemd-activate -l 19531 /usr/lib/systemd/systemd-journal-gatewayd

See Also

systemd(1), systemd.socket(5), systemd.service(5), cat(1)


Explore man page connections for systemd-activate(8).