Nagios Support Forum

can Nagios scan a log file for a keyword? like search for a particular string from log files and send out an alert

You can monitor log files for a specific regular expression with the check log files plugin.
check_logfiles

Managing Plugins in Nagios XI

thank you, but i do not see anywhere to download the plugin you provided, usually there is always an option to download or copy the script but i do not see it, all i see is this https://labs.consol.de/nagios/check_log ... stallation which just basically explains the plugin, am confused as to which is the actually plugin

Whups! Sorry about that. It looks like the same plugin is posted on GitHub as well. You should be able to download it from there.
check_logfiles on GitHub

You may already have a plugin called check log installed. It looks like you can search for a query in a log file using the -q flag.