NAME

       init-d-script — interpreter for short and simple init.d scripts

DESCRIPTION

       Generic  init.d  script framework to reduce the redundant code in /etc/init.d/.  The goal is to create an
       init.d script that is Debian and LSB compliant.  When the Debian  policy  conflicts  with  the  LSB,  the
       Debian policy takes precedence.

       This  is  a  simple  example  on  how  init-d-script can be used to start and stop a daemon with PID file
       support:

             #!/usr/bin/env /lib/init/init-d-script
             ### BEGIN INIT INFO
             # Provides:          atd
             # Required-Start:    $syslog $time $remote_fs
             # Required-Stop:     $syslog $time $remote_fs
             # Default-Start:     2 3 4 5
             # Default-Stop:      0 1 6
             # Short-Description: run at jobs
             # Description:       Debian init script to start the daemon
             #                    running at jobs.
             ### END INIT INFO
             DAEMON=/usr/sbin/atd

       The following variables affect behaviour of an init script:

       DAEMON       Path to daemon being started.  If the init script is not  supposed  to  start  any  kind  of
                    daemon,  the  functions  do_start_override(),  do_stop_override()  and  do_status_override()
                    should be defined instead.

       DAEMON_ARGS  Additional arguments, passed to daemon during start.

       NAME         Additional environment variables are sources  from  /etc/default/${NAME}.   If  unset,  this
                    variable defaults to the basename of the “DAEMON” value.

       COMMAND_NAME
                    If   this   variable   is   set,   it   is   used  as  argument  to  the  --name  option  of
                    start-stop-daemon(8).  It may be useful if the value of the NAME variable is too long.

       PIDFILE      Path to file where the process identifier of the started daemon will be stored during start.
                    If the value is verbatim “none”, the process identifier will not be stored in any file.   If
                    this variable is not set, it gets a sensible default value, so it is rarely necessary to set
                    this variable explicitly.

       Additionally,  it is possible to change the behaviour of the resulting shell script by overriding some of
       the internal functions.  To do so, define function  with  an  _override  suffix.   So,  for  example,  to
       override  the  do_status() function, one should define a do_status_override() function.  The exception to
       this rule is the do_reload() function, whose  override  should  be  defined  as-is,  without  the  above-
       mentioned suffix.

       Here is a control flow chart that explains what functions are called and when:

             /etc/init.d/script start
               do_start
                 do_start_prepare # no-op
                 do_start_cmd     # start-stop-daemon is called here
                 do_start_cleanup # no-op

             /etc/init.d/script stop
               do_stop
                 do_stop_prepare # no-op
                 do_stop_cmd     # start-stop-daemon is called here
                 do_stop_cleanup # no-op

             /etc/init.d/script status
               do_status

             /etc/init.d/script reload
               do_reload
                 do_usage
                 exit 3

             /etc/init.d/script force-reload
               do_force_reload
                 do_reload   # if overridden
                 do_restart
                   do_restart_prepare
                   do_stop_cmd
                   do_start_cmd
                   do_restart_cleanup

             /etc/init.d/script restart
               do_force_restart
             /etc/init.d/script try-restart
               if do_status; then
                 do_restart
                   do_restart_prepare
                   do_stop_cmd  # start-stop-daemon is called here
                   do_start_cmd # start-stop-daemon is called here
                   do_restart_cleanup

             /etc/init.d/script <arg>
               do_unknown <arg>
                 exit 3

             /etc/init.d/script
               do_usage

       As  can  be  seen, by default, the script does not support the reload action; it should be implemented by
       the script writer by defining a do_reload() function.

       If the daemon performs reload action upon receiving a SIGUSR1 signal, a  generic  implementation  can  be
       used with the following code:

             alias do_reload=do_reload_sigusr1

SEE ALSO

       inittab(8), service(8), update-rc.d(8).

AUTHORS

       Petter Reinholdtsen <pere@debian.org>

Debian                                           August 5, 2019                                 INIT-D-SCRIPT(5)