start-stop-daemon(8)              dpkg suite              start-stop-daemon(8)

       start-stop-daemon - start and stop system daemon programs

       start-stop-daemon [option...] command

       start-stop-daemon  is  used  to control the creation and termination of
       system-level  processes.   Using   one   of   the   matching   options,
       start-stop-daemon  can  be  configured  to find existing instances of a
       running process.

       Note:  unless  --pid  or  --pidfile  are  specified,  start-stop-daemon
       behaves similar to killall(1).  start-stop-daemon will scan the process
       table looking for any processes which match the  process  name,  parent
       pid,  uid, and/or gid (if specified). Any matching process will prevent
       --start from starting the daemon. All matching processes will  be  sent
       the  TERM  signal  (or  the  one  specified via --signal or --retry) if
       --stop is specified. For daemons which have long-lived  children  which
       need to live through a --stop, you must specify a pidfile.

       -S, --start [--] arguments
              Check  for  the  existence  of  a  specified process.  If such a
              process exists, start-stop-daemon does nothing, and  exits  with
              error  status 1 (0 if --oknodo is specified).  If such a process
              does  not  exist,  it  starts  an  instance,  using  either  the
              executable  specified  by --exec or, if specified, by --startas.
              Any arguments given after -- on  the  command  line  are  passed
              unmodified to the program being started.

       -K, --stop
              Checks  for  the  existence  of  a specified process.  If such a
              process exists, start-stop-daemon sends it the signal  specified
              by  --signal,  and exits with error status 0.  If such a process
              does not exist, start-stop-daemon exits with error status  1  (0
              if  --oknodo  is  specified).  If  --retry  is  specified,  then
              start-stop-daemon  will  check   that   the   process(es)   have

       -T, --status
              Check  for  the existence of a specified process, and returns an
              exit status code, according  to  the  LSB  Init  Script  Actions
              (since version 1.16.1).

       -H, --help
              Show usage information and exit.

       -V, --version
              Show the program version and exit.

   Matching options
       --pid pid
              Check  for  a  process  with  the  specified  pid (since version
              1.17.6).  The pid must be a number greater than 0.

       --ppid ppid
              Check for a process with the specified parent  pid  ppid  (since
              version 1.17.7).  The ppid must be a number greater than 0.

       -p, --pidfile pid-file
              Check whether a process has created the file pid-file.

              Note:  using  this  matching option alone might cause unintended
              processes to be acted on, if the old process terminated  without
              being able to remove the pid-file.

              Warning:  using  this match option with a world-writable pidfile
              or using it alone with a daemon that writes the  pidfile  as  an
              unprivileged  (non-root)  user  will  be  refused  with an error
              (since version 1.19.3) as  this  is  a  security  risk,  because
              either  any  user  can  write  to  it,  or  if  the  daemon gets
              compromised, the contents of the pidfile cannot be trusted,  and
              then  a  privileged  runner  (such as an init script executed as
              root)  would  end  up  acting  on  any  system  process.   Using
              /dev/null is exempt from these checks.

       -x, --exec executable
              Check  for  processes that are instances of this executable. The
              executable argument should be an absolute pathname.  Note:  this
              might  not  work  as  intended  with interpreted scripts, as the
              executable will point to  the  interpreter.  Take  into  account
              processes  running from inside a chroot will also be matched, so
              other match restrictions might be needed.

       -n, --name process-name
              Check for processes with the name process-name. The process-name
              is  usually the process filename, but it could have been changed
              by the process itself. Note: on most systems this information is
              retrieved  from  the  process  comm  name from the kernel, which
              tends to have a relatively short  length  limit  (assuming  more
              than 15 characters is non-portable).

       -u, --user username|uid
              Check  for  processes owned by the user specified by username or
              uid. Note: using this  matching  option  alone  will  cause  all
              processes matching the user to be acted on.

   Generic options
       -g, --group group|gid
              Change to group or gid when starting the process.

       -s, --signal signal
              With  --stop,  specifies  the  signal to send to processes being
              stopped (default TERM).

       -R, --retry timeout|schedule
              With  --stop,  specifies  that  start-stop-daemon  is  to  check
              whether  the  process(es)  do  finish.  It will check repeatedly
              whether any matching processes are running, until none  are.  If
              the  processes  do  not exit it will then take further action as
              determined by the schedule.

              If timeout is specified instead of schedule, then  the  schedule
              signal/timeout/KILL/timeout  is used, where signal is the signal
              specified with --signal.

              schedule is a list of at least two items  separated  by  slashes
              (/);  each  item  may be -signal-number or [-]signal-name, which
              means to send that signal, or timeout, which means to wait  that
              many  seconds  for processes to exit, or forever, which means to
              repeat the rest of the schedule forever if necessary.

              If the end of  the  schedule  is  reached  and  forever  is  not
              specified, then start-stop-daemon exits with error status 2.  If
              a schedule is specified, then any signal specified with --signal
              is ignored.

       -a, --startas pathname
              With  --start,  start the process specified by pathname.  If not
              specified, defaults to the argument given to --exec.

       -t, --test
              Print actions that would be taken  and  set  appropriate  return
              value, but take no action.

       -o, --oknodo
              Return  exit  status 0 instead of 1 if no actions are (would be)

       -q, --quiet
              Do  not  print  informational  messages;  only   display   error

       -c, --chuid username|uid[:group|gid]
              Change to this username/uid before starting the process. You can
              also specify a group by appending a :, then the group or gid  in
              the same way as you would for the chown(1) command (user:group).
              If a user is specified without a group, the primary GID for that
              user  is used.  When using this option you must realize that the
              primary and supplemental groups are set as  well,  even  if  the
              --group  option is not specified. The --group option is only for
              groups that the user isn't normally a member of (like adding per
              process group membership for generic users like nobody).

       -r, --chroot root
              Chdir  and  chroot  to  root before starting the process. Please
              note that the pidfile is also written after the chroot.

       -d, --chdir path
              Chdir to path before starting the process. This  is  done  after
              the chroot if the -r|--chroot option is set. When not specified,
              start-stop-daemon  will  chdir  to  the  root  directory  before
              starting the process.

       -b, --background
              Typically  used  with  programs  that don't detach on their own.
              This option will force start-stop-daemon to fork before starting
              the  process,  and  force  it  into  the  background.   Warning:
              start-stop-daemon cannot check the exit status  if  the  process
              fails  to  execute for any reason. This is a last resort, and is
              only meant for programs that either make  no  sense  forking  on
              their  own,  or where it's not feasible to add the code for them
              to do this themselves.

              Wait for the background process to send a readiness notification
              before  considering  the service started (since version 1.19.3).
              This implements parts of  the  systemd  readiness  protocol,  as
              specified in the sd_notify(3) man page.  The following variables
              are supported:

                     The program is ready to give  service,  so  we  can  exit

                     The  program  requests  to  extend  the timeout by number
                     microseconds.  This will reset the current timeout to the
                     specified value.

                     The  program  is  exiting with an error.  Do the same and
                     print the user-friendly string for the errno value.

              Set a timeout  for  the  --notify-await  option  (since  version
              1.19.3).   When  the  timeout is reached, start-stop-daemon will
              exit with an error code, and no readiness notification  will  be
              awaited.  The default is 60 seconds.

       -C, --no-close
              Do  not  close  any file descriptor when forcing the daemon into
              the background  (since  version  1.16.5).   Used  for  debugging
              purposes  to  see  the  process  output,  or  to  redirect  file
              descriptors to log the process output.  Only relevant when using

       -N, --nicelevel int
              This alters the priority of the process before starting it.

       -P, --procsched policy:priority
              This  alters  the  process  scheduler policy and priority of the
              process before starting it (since version 1.15.0).  The priority
              can  be  optionally  specified  by appending a : followed by the
              value. The default priority is 0. The currently supported policy
              values are other, fifo and rr.

       -I, --iosched class:priority
              This  alters  the IO scheduler class and priority of the process
              before starting it (since version 1.15.0).  The priority can  be
              optionally specified by appending a : followed by the value. The
              default priority is 4, unless class is idle, then priority  will
              always  be 7. The currently supported values for class are idle,
              best-effort and real-time.

       -k, --umask mask
              This sets the umask of the process  before  starting  it  (since
              version 1.13.22).

       -m, --make-pidfile
              Used  when  starting  a program that does not create its own pid
              file. This option will make start-stop-daemon  create  the  file
              referenced  with --pidfile and place the pid into it just before
              executing the process. Note, the file will only be removed  when
              stopping  the  program  if --remove-pidfile is used.  Note: This
              feature may not work in all cases. Most notably when the program
              being  executed forks from its main process. Because of this, it
              is usually only  useful  when  combined  with  the  --background

              Used  when  stopping  a program that does not remove its own pid
              file  (since  version   1.17.19).    This   option   will   make
              start-stop-daemon  remove  the  file  referenced  with --pidfile
              after terminating the process.

       -v, --verbose
              Print verbose informational messages.

       0      The requested action was performed. If --oknodo  was  specified,
              it's also possible that nothing had to be done.  This can happen
              when --start was specified and a matching  process  was  already
              running, or when --stop was specified and there were no matching

       1      If --oknodo was not specified and nothing was done.

       2      If --stop and  --retry  were  specified,  but  the  end  of  the
              schedule was reached and the processes were still running.

       3      Any other error.

       When  using  the  --status  command,  the  following  status  codes are

       0      Program is running.

       1      Program is not running and the pid file exists.

       3      Program is not running.

       4      Unable to determine program status.

       Start the food daemon, unless one is already running (a  process  named
       food, running as user food, with pid in

              start-stop-daemon --start --oknodo --user food --name food \
                   --pidfile /run/ --startas /usr/sbin/food \
                   --chuid food -- --daemon

       Send SIGTERM to food and wait up to 5 seconds for it to stop:

              start-stop-daemon --stop --oknodo --user food --name food \
                   --pidfile /run/ --retry 5

       Demonstration of a custom schedule for stopping food:

              start-stop-daemon --stop --oknodo --user food --name food \
                   --pidfile /run/ --retry=TERM/30/KILL/5

1.19.7                            2022-05-25              start-stop-daemon(8)
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