How can I log the stdout of a process started by start-stop-daemon?
I am using an init script to run a simple process, which is started with:
start-stop-daemon --start --quiet --chuid $DAEMONUSER \ --make-pidfile --pidfile $PIDFILE --background \ --exec $DAEMON $DAEMON_ARGS
The process called $DAEMON usually prints log information to its standard output. As far as I can tell this data is not being stored anywhere.
I would like to write or append the stdout of $DAEMON to a file somewhere.
The only solution I know is to tell start-stop-daemon to call a shellscript instead of $DAEMON directly; the script then calls $DAEMON and writes to the logfile. But that requires an extra script which, like modifying the daemon itself, seems the wrong way to solve such a common task.
To expand on ypocat's answer, since it won't let me comment:
start-stop-daemon --start --quiet --chuid $DAEMONUSER \ --make-pidfile --pidfile $PIDFILE --background \ --startas /bin/bash -- -c "exec $DAEMON $DAEMON_ARGS > /var/log/some.log 2>&1"
exec to run the daemon allows stop to correctly stop the child process instead of just the bash parent.
--startas instead of
--exec ensures that the process will be correctly detected by its pid and won't erroneously start multiple instances of the daemon if start is called multiple times. Otherwise, start-stop-daemon will look for a /bin/bash process and ignore the actual child process running the daemon.