Updated: April 19, 2023

Make entries in the system log (POSIX)

Note: If you aren't root, specify the full path: /usr/sbin/logger.


logger [-is] [-f file] [-p pri] [-t tag] 
       [string ...]

Runs on:

QNX Neutrino


-f file
(QNX Neutrino extension) Log the specified file.
(QNX Neutrino extension) Log the process ID of the logger process with each line.
-p pri
(QNX Neutrino extension) 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(s) as informational level in the local3 facility. The default is user.notice.
(QNX Neutrino extension) Log the message to standard error, as well as the system log.
-t tag
(QNX Neutrino extension) Mark every line in the log with the specified tag. The default is the current user ID.
Write the string arguments to the log, separated by a single space; if not specified, and the -f flag isn't provided, standard input is logged.


The logger command provides a shell command interface to the syslogd daemon.


Log the message “System rebooted”:

logger System rebooted

Log the contents of the file /tmp/log, tagging each line with log:

logger -f /tmp/log -t log


The logger utility is located in the /usr/sbin/ directory, which is not included in the default PATH of non-root users. If you aren't root, specify the full path.

Environment variables:

When defined, SYSLOG specifies which node syslogd is running on. By default, the local node is assumed.

Exit status:

Successful completion.
An error occurred.
Note: Because the syslog() API doesn't return error codes, only argument errors can be detected.