start-stop-daemon
start and stop system daemon programs
Synopsis
start-stop-daemon
[option...] command
add an example, a script, a trick and tips
examples
source
start-stop-daemon --stop --pidfile
/opt/athena/run/athena.pid
source
mv /sbin/start-stop-daemon
/sbin/start-stop-daemon.REAL
dd of=/sbin/start-stop-daemon <<EOF
#!/bin/sh
echo
echo "Warning: Fake start-stop-daemon called,
doing nothing"
echo "Warning: Fake start-stop-daemon
called, doing nothing"
EOF
chmod 755 /sbin/start-stop-daemon
mv /sbin/initctl /sbin/initctl.REAL
description
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
--pidfile is 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, 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.
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) taken.
-q,
--quiet
Do not print informational
messages; only display error messages.
-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’ 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.
-C,
--no-close
Do not close any file
descriptor when forcing the daemon into the background. Used
for debugging purposes to see the process output, or to
redirect file descriptors to log the process output. Only
relevant when using --background.
-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. 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. 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.
-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 not be removed when stopping the program.
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
option.
-v,
--verbose
Print verbose informational
messages.
commands
-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 terminated.
-T, --status
Check for the existence of a specified process, and returns an
exit status code, according to the LSB Init Script Actions.
-H, --help
Show usage information and exit.
-V, --version
Show the program version and exit.
example
Start the food daemon, unless one is already running (a
process named food, running as user food, with pid in food.pid):
start-stop-daemon --start --oknodo --user food --name food \
--pidfile /run/food.pid --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/food.pid --retry 5
Demonstration of a custom schedule for stopping food:
start-stop-daemon --stop --oknodo --user food --name food \
--pidfile /run/food.pid --retry=TERM/30/KILL/5
exit status
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 processes.
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 returned:
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.
matching options
-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.
-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.