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DAEMON(8)		  BSD System Manager's Manual		     DAEMON(8)

NAME
     daemon -- run detached from the controlling terminal

SYNOPSIS
     daemon [-cfrS] [-p	child_pidfile] [-P supervisor_pidfile] [-t title]
	    [-u	user] [-m output_mask] [-o output_file]	[-s syslog_priority]
	    [-T	syslog_tag] [-l	syslog_facility] [-R restart_delay_seconds]
	    command arguments ...

DESCRIPTION
     The daemon	utility	detaches itself	from the controlling terminal and exe-
     cutes the program specified by its	arguments.  Privileges may be lowered
     to	the specified user.  The output	of the daemonized process may be redi-
     rected to syslog and to a log file.

     The options are as	follows:

     -c	     Change the	current	working	directory to the root ("/").

     -f	     Redirect standard input, standard output and standard error to
	     /dev/null.

     -S	     Enable syslog output.  This is implicitly applied if other	syslog
	     parameters	are provided.  The default values are daemon, notice,
	     and daemon	for facility, priority,	and tag, respectively.

     -o	output_file
	     Append output from	the daemonized process to output_file.	If the
	     file does not exist, it is	created	with permissions 0600.

     -m	output_mask
	     Redirect output from the child process stdout (1),	stderr (2), or
	     both (3).	This value specifies what is sent to syslog and	the
	     log file.	The default is 3.

     -p	child_pidfile
	     Write the ID of the created process into the child_pidfile	using
	     the pidfile(3) functionality.  The	program	is executed in a
	     spawned child process while the daemon waits until	it terminates
	     to	keep the child_pidfile locked and removes it after the process
	     exits.  The child_pidfile owner is	the user who runs the daemon
	     regardless	of whether the -u option is used or not.

     -P	supervisor_pidfile
	     Write the ID of the daemon	process	into the supervisor_pidfile
	     using the pidfile(3) functionality.  The program is executed in a
	     spawned child process while the daemon waits until	it terminates
	     to	keep the supervisor_pidfile locked and removes it after	the
	     process exits.  The supervisor_pidfile owner is the user who runs
	     the daemon	regardless of whether the -u option is used or not.

     -r	     Supervise and restart the program after a one-second delay	if it
	     has been terminated.

     -R	restart_delay_seconds
	     Supervise and restart the program after the specified delay if it
	     has been terminated.

     -t	title
	     Set the title for the daemon process.  The	default	is the daemo-
	     nized invocation.

     -u	user
	     Login name	of the user to execute the program under.  Requires
	     adequate superuser	privileges.

     -s	syslog_priority
	     These priorities are accepted: emerg, alert, crit,	err, warning,
	     notice, info, and debug.  The default is info.

     -l	syslog_facility
	     These facilities are accepted: auth, authpriv, console, cron,
	     daemon, ftp, kern,	lpr, mail, news, ntp, security,	syslog,	user,
	     uucp, and local0, ..., local7.  The default is daemon.

     -T	syslog_tag
	     Set the tag which is appended to all syslog messages.  The	de-
	     fault is daemon.

     If	any of the options -p, -P, -r, -o, -s, -T, -m, -S, or -l are speci-
     fied, the program is executed in a	spawned	child process.	The daemon
     waits until it terminates to keep the pid file(s) locked and removes them
     after the process exits or	restarts the program.  In this case if the
     monitoring	daemon receives	software termination signal (SIGTERM) it for-
     wards it to the spawned process.  Normally	it will	cause the child	to
     exit, remove the pidfile(s) and then terminate.

     If	neither	file or	syslog output are selected, all	output is redirected
     to	the daemon process and written to stdout.  The -f option may be	used
     to	suppress the stdout output completely.

     The -P option is useful combined with the -r option as supervisor_pidfile
     contains the ID of	the supervisor not the child.  This is especially im-
     portant if	you use	-r in an rc script as the -p option will give you the
     child's ID	to signal when you attempt to stop the service,	causing	daemon
     to	restart	the child.

EXIT STATUS
     The daemon	utility	exits 1	if an error is returned	by the daemon(3) li-
     brary routine, 2 if child_pidfile or supervisor_pidfile is	requested, but
     cannot be opened, 3 if process is already running (pidfile	exists and is
     locked), 4	if syslog_priority is not accepted, 5 if syslog_facility is
     not accepted, 6 if	output_mask is not within the accepted range, 7	if
     output_file cannot	be opened for appending, and otherwise 0.

DIAGNOSTICS
     If	the command cannot be executed,	an error message is printed to stan-
     dard error.  The exact behavior depends on	the logging parameters and the
     -f	flag.

SEE ALSO
     setregid(2), setreuid(2), daemon(3), exec(3), pidfile(3), termios(4),
     tty(4)

HISTORY
     The daemon	utility	first appeared in FreeBSD 4.7.

BSD				April 15, 2018				   BSD

NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | DIAGNOSTICS | SEE ALSO | HISTORY

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