This is not my article, it is copy from this site . It cover install icinga2 , icinga2 director and pnp4nagios on Ubuntu 20.04, but is very useful as manual for debian buster and Bullseye.

This guide shows how to install Icinga2 monitoring software on Ubuntu 20.04 – this includes backend, frontend, director and pnp4nagios (adding graphs to icinga). Especially PNP was hard to get working – but if you follow the guide everything is nicely lined up at the end.

The cut command is a command-line utility for cutting sections from each line of a file. It writes the result to the standard output. It’s worth noting that it does not modify the file, but only works on a copy of the content. Although typically the input to a cut command is a file, we can pipe the output of other commands and use it as input.

It can be used to cut parts of a line by byte position, character and field. Basically the cut command slices a line and extracts the text. It is necessary to specify option with command otherwise it gives error. If more than one file name is provided then data from each file is not precedes by its file name.