How to use a parameter in ExecStart command line

Question

I try to convert a SysVintit script used on Debian  and derivatives distros such as LinuxMint and Ubuntu  amp  Co   to a systemd service to be used on Fedora or ArchLinux  and derivative distros such as Bridge or Manjaro   but even if the systemd start system is more performant and versatile than the previous  I don t understand how to make simple stuff such as using an  optional  argument on a command line like ExecStart  or ExecRestart     Here is what I do with SysVinit      bin sh     BEGIN INIT INFO   Provides           myprog   Required-Start      remote fs  syslog   Required-Stop       remote fs  syslog   Default-Start      2 3 4 5   Default-Stop       0 1 6   Short-Description  myprog init script   Descripton         this script manages myprog     END INIT INFO   exit if myprog isn t installed   -x   opt mystuff myrpog       exit 0 case   1  in   start      cd  opt mystuff       myprog -r     echo          stop      cd  opt mystuff       myprog -x          restart      cd  opt mystuff       myprog -x  amp  amp    myprog -r          version      cd  opt mystuff       myprog -v          try      cd  opt mystuff       myprog                 echo  Usage  sudo service myprog  start stop version try    gt  amp 2     exit 3        esac     So the script above allows to use different arguments including an empty one that will display the message  Usage       when using the following command lines   sudo service myprog start     gt  start myprog with the -r argument  sudo service myprog stop      gt  stop myprog with the -x argument  sudo service myprog version   gt  display the release of myprog in the console  sudo service myprog try       gt  start myprog without any argument  sudo service myprog restart   gt  stop then start myprog with the -r argument  suso service myprog           gt  display the  Usage      message in the console   Now  with systemd  the script should look like this     Unit  Description This script manages myprog ConditionFileExecutable  opt mystuff myprog   Service  Type oneshot RemainAfterExit yes ExecStart  opt mystuf myprog -r ExecStop  opt mystuff myprog -x ExecRestart  opt mystuff myprog -x    opt mystuff myprog -r   Install  After NetworkManager service   Here starts my problems  and my lack of systemd knowledge    Obviously  systemd doesn t provide a command such as ExecCustom01   ExecCustom02  etc  that would allow me to create commands for  version  and  try   and other if needed    So  I may use ExecRestart in a different maner if I could use an argument to start both the  version  or the  try  command  being said that the  real  restart may be done by starting successively the stop and the start commands    These  customized  ExecRestart  command could then look like this   sudo systemctl restart myprog    gt  without argument for the  try  command   and   sudo systemctl restart myprog -v   gt  for the  version  command   The systemd script could then look like this    Unit  Description This script manages myprog ConditionFileExecutable  opt mystuff myprog   Service  Type oneshot RemainAfterExit yes ExecStart  opt mystuf myprog -r ExecStop  opt mystuff myprog -x ExecRestart  opt mystuff myprog          this is where I need to use an argument   Install  After NetworkManager service   But I don t know if it s possible  and if yes  what is the syntax to use   Any help would be trully appreciated since even after spending a bunch of hours in the multiple systemd man pages  I couldn t find any explicit sample about how to do that   TIA for your time and advice

User · Answer

Although systemd indeed does not provide way to pass command-line arguments for unit files, there are possibilities to write instances: http://0pointer.de/blog/projects/instances.html

For example: /lib/systemd/system/[email protected] looks something like this:

[Unit]
Description=Serial Getty on %I
BindTo=dev-%i.device
After=dev-%i.device systemd-user-sessions.service

[Service]
ExecStart=-/sbin/agetty -s %I 115200,38400,9600
Restart=always
RestartSec=0

So, you may start it like:

$ systemctl start [email protected]
$ systemctl start [email protected]

For systemd it will different instances:

$ systemctl status [email protected]
[email protected] - Getty on ttyUSB0
      Loaded: loaded (/lib/systemd/system/[email protected]; static)
      Active: active (running) since Mon, 26 Sep 2011 04:20:44 +0200; 2s ago
    Main PID: 5443 (agetty)
      CGroup: name=systemd:/system/[email protected]/ttyUSB0
          + 5443 /sbin/agetty -s ttyUSB0 115200,38400,9600

It also mean great possibility enable and disable it separately.

Off course it lack much power of command line parsing, but in common way it is used as some sort of config files selection. For example you may look at Fedora [email protected]: http://pkgs.fedoraproject.org/cgit/openvpn.git/tree/[email protected]

User · Answer

To attempt command line arguments directly is not possible   One alternative might be environment variables  https   superuser com questions 728951 systemd-giving-my-service-multiple-arguments    This is where I found the answer  http   www freedesktop org software systemd man systemctl html  so sudo systemctl restart myprog -v -- systemctl will think you re trying to set one of its flags  not myprog s flag   sudo systemctl restart myprog someotheroption -- systemctl will restart myprog and the someotheroption service  if it exists

[systemd] How to use a parameter in ExecStart command line?

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