tail head cat sleep
QR code linking to this page

Manual Pages  — LOGGER


logger – make entries in the system log



logger [-46Ais] [-f file] [-H hostname] [-h host] [-P port] [-p pri] [-S addr:port] [-t tag] [message ...]


The logger utility provides a shell command interface to the syslog(3) system log module.

The following options are available:
  Force logger to use IPv4 addresses only.
  Force logger to use IPv6 addresses only.
  By default, logger tries to send the message to only one address, even if the host has more than one A or AAAA record. If this option is specified, logger tries to send the message to all addresses.
  Log the process id of the logger process with each line.
  Log the message to standard error, as well as the system log.
-f file
  Read the contents of the specified file into syslog. This option is ignored when a message is also specified.
-H hostname
  Set the hostname in the header of the message to specified value. If not specified, host part of gethostname(3) will be used.
-h host
  Send the message to the remote system host instead of logging it locally. Note that logger currently supports AF_INET (IPv4), AF_INET6 (IPv6), and AF_LOCAL (Unix-domain socket) address families. The following address formats are valid in host:

AF_INET6 2001:db8::1
AF_LOCAL /var/run/log
-P port
  Send the message to the specified port number on a remote system, which can be specified as a service name or as a decimal number. The default is "syslog". If an unknown service name is used, logger prints a warning and falls back to port 514.
-p pri
  Enter the message with the specified priority. The priority may be specified numerically or as a facility.level pair. For example, "-plocal3.info" logs the message(s) as informational level in the local3 facility. The default is "user.notice".
-S addr:port
  Specify source address and/or source port when using -h option. The same address will be used for all of the remote addresses when -A flag is enabled. Note that a numeric IPv6 address in addr must be enclosed with "[" and "]".
-t tag
  Mark every line in the log with the specified tag rather than the default of current login name.
message Write the message to log; if not specified, and the -f flag is not provided, standard input is logged.


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


logger System rebooted

logger -p local0.notice -t HOSTIDM -f /dev/idmc


syslog(3), syslogd(8)


The logger command is expected to be IEEE Std 1003.2 ("POSIX.2") compatible.

LOGGER (1) December 5, 2017

tail head cat sleep
QR code linking to this page

Please direct any comments about this manual page service to Ben Bullock. Privacy policy.

As soon as we started programming, we found to our surprise that it wasn't as easy to get programs right as we had thought. Debugging had to be discovered. I can remember the exact instant when I realized that a large part of my life from then on was going to be spent in finding mistakes in my own programs.
— Maurice Wilkes