logger

logger does by hand what daemons do: it hands one line to the local syslog daemon (through /dev/log), which files it and forwards it wherever its rules say. Use it to test a logging setup end to end: log a line on the device, look for it on the collector. -p facility.severity sets the PRI, -t the tag.

logger command usage

logger [-t TAG] [-p FACILITY.SEVERITY] MESSAGE

Options

-t app

the tag: the program name shown before the message

-p local0.err

facility and severity (default user.notice)

-s

also print the line on standard error

logger examples

logger -t app 'order 1001 paid'

Logs one line tagged app, as user.notice.

logger -p auth.warning -t sshd 'Failed password for root'

Logs a line as facility auth, severity warning.

for level in debug info warning err; do logger -p daemon.$level "test $level"; done

Logs one line at each of four severities, to test a filter.

Pitfalls

• BusyBox's logger only writes to the local daemon: to reach a collector, that daemon must forward.
• The line is filed under the local host name; a collector shows it in that host's file.

Run it on real machines