daemon(8) [freebsd man page]
DAEMON(8) BSD System Manager's Manual DAEMON(8) NAME
daemon -- run detached from the controlling terminal SYNOPSIS
daemon [-cfr] [-p child_pidfile] [-P supervisor_pidfile] [-u user] command arguments ... DESCRIPTION
The daemon utility detaches itself from the controlling terminal and executes the program specified by its arguments. Privileges may be low- ered to the specified user. 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. -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 if it has been terminated. -u user Login name of the user to execute the program under. Requires adequate superuser privileges. If the -p, -P or -r option is specified 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 forwards it to the spawned process. Normally it will cause the child to exit, remove the pidfile(s) and then terminate. 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 important 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) library 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), otherwise 0. DIAGNOSTICS
If the command cannot be executed, an error message is displayed on standard error unless the -f flag is specified. 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
September 13, 2013 BSD
Check Out this Related Man Page
KEEPALIVED(8) System Manager's Manual KEEPALIVED(8) NAME
keepalived - load-balancing and high-availability service SYNOPSIS
keepalived [-f|--use-file=FILE] [-P|--vrrp] [-C|--check] [-l|--log-console] [-D|--log-detail] [-S|--log-facility={0-7}] [-V|--dont-release-vrrp] [-I|--dont-release-ipvs] [-R|--dont-respawn] [-n|--dont-fork] [-d|--dump-conf] [-p|--pid=FILE] [-r|--vrrp_pid=FILE] [-c|--checkers_pid=FILE] [-v|--version] [-h|--help] DESCRIPTION
Keepalived provides simple and robust facilities for load-balancing and high-availability. The load-balancing framework relies on well-known and widely used Linux Virtual Server (IPVS) kernel module providing Layer4 load-balancing. Keepalived implements a set of checkers to dynamically and adaptively maintain and manage load-balanced server pool according their health. Keepalived also implements the VRRPv2 protocol to achieve high-availability with director failover. OPTIONS
-f, --use-file=FILE Use the specified configuration file. The default configuration file is "/etc/keepalived/keepalived.conf". -P, --vrrp Only run the VRRP subsystem. This is useful for configurations that do not use IPVS load balancer. -C, --check Only run the healthcheck subsystem. This is useful for configurations that use the IPVS load balancer with a single director with no failover. -l, --log-console Log messages to the local console. The default behavior is to log messages to syslog. -D, --log-detail Detailed log messages. -S, --log-facility=[0-7] Set syslog facility to LOG_LOCAL[0-7]. The default syslog facility is LOG_DAEMON. -V, --dont-release-vrrp Don't remove VRRP VIPs and VROUTEs on daemon stop. The default behavior is to remove all VIPs and VROUTEs when keepalived exits -I, --dont-release-ipvs Don't remove IPVS topology on daemon stop. The default behavior it to remove all entries from the IPVS virtual server table on when keepalived exits. -R, --dont-respawn Don't respawn child processes. The default behavior is to restart the VRRP and checker processes if either process exits. -n, --dont-fork Don't fork the daemon process. This option will cause keepalived to run in the foreground. -d, --dump-conf Dump the configuration data. -p, --pid=FILE Use specified pidfile for parent keepalived process. The default pidfile for keepalived is "/var/run/keepalived.pid". -r, --vrrp_pid=FILE Use specified pidfile for VRRP child process. The default pidfile for the VRRP child process is "/var/run/keepalived_vrrp.pid". -c, --checkers_pid=FILE Use specified pidfile for checkers child process. The default pidfile for the checker child process is "/var/run/keepalived_checkers.pid". -v, --version Display the version and exit. -h, --help Display this help message and exit. SEE ALSO
keepalived.conf(5), ipvsadm(8) AUTHOR
This man page was written by Ryan O'Hara <rohara@redhat.com> November 2012 KEEPALIVED(8)