Linux 'logger' Command

Manually add log entries to the Linux syslog file

Start-up Team working together In Their Office

vgajic/Getty Images

The Linux logger utilities makes entries in the system log. It provides a shell command interface to the syslog system-log module.

Synopsis

The command takes the following general form:

logger [-isd ] [-f file ] [-p pri ] [-t tag ] [-u socket ] [message ... ] 

Command Switches

Extend the performance of the logger command using the following switches:

  • -i: Log the process id of the logger process with each line.
  • -s: Log the message to standard error, as well as the system log.
  • -f file: Log the specified file.
  • -p pri: Enter the message with the specified priority. The priority may be specified numerically or as a facility.level pair. For example, -p local3.info logs the message as informational level in the local3 facility. The default is user.notice.
  • -t tag: Mark every line in the log with the specified tag.
  • -u sock: Write to socket as specified with socket instead of builtin syslog routines.
  • -d: Use a datagram instead of a stream connection to this socket.
  • --: End the argument list. This is to allow the message to start with a hyphen.
  • message: Write the message to log; if not specified, and the -f flag is not provided, standard input is logged.

Information About the 'logger' Program

The logger utility exits 0 on success, and >0 if an error occurs.

Valid facility names are: auth, authpriv (for security information of a sensitive nature), cron, daemon, ftp, kern, lpr, mail, news, security (deprecated synonym for auth), syslog, user, uucp, and local0 to local7, inclusive.

Valid level names are: alert, crit, debug, emerg, err, error (deprecated synonym for err), info, notice, panic (deprecated synonym for emerg), warning, warn (deprecated synonym for warning). For the priority order and intended purposes of these levels, see the manpage for syslog

Examples

logger command

Although the syslog file varies in its location, on Ubuntu it appears at /var/log/syslog. Write sample messages to the log as follows:

logger -is -p local0.info "Sample log written to /var/log."

Use the man command (% man) to see how a command is used on your particular computer.