Logs messages to the system log (/var/log/system.log). Command-line messages are logged if provided. Otherwise, messages are read and logged, line-by-line, from the file provided via -f. If no such file is given, logger reads messages from standard input.
Read and log messages from
Log the PID of the logger process with each message.
Log each message with the given
priority. Priorities have the form
level. The default is user.notice. See syslog(3) for more information.
Also log messages to standard error.
tag to each message line.
Warn about upcoming trouble:
logger -p user.emerg 'Intruder Alert! Intruder Alert!'