The logger command provides an easy way to add log files to /var/log/syslog — from the command line, from scripts, or from other files. In today’s post, we’ll take a look at how it works.
How easy is easy?
This easy. Just type logger <message> on the command line and your message will be added to the end of the /var/log/syslog file.
$ logger comment to be added to log $ tail -1 /vvar/log/syslog May 21 18:02:16 butterfly shs: comment to be added to log
You can also add the output from commands by enclosing the commands in backticks.
$ logger `who` $ tail -1 /var/log/syslog May 21 18:02:43 butterfly shs: shs pts/0 2018-05-21 15:57 (192.168.0.15)
Content from a file
The contents of text files can be added by using the -f option. Put the name of the file to be added to the log following the -f option as shown below.