Mawk is a version of the awk programming language. Awk interprets a special-purpose programming language to do quick text pattern matching and reformatting. Mawk improves on awk in certain ways and can sometimes outperform gawk, the standard awk program for Linux. Mawk conforms to the POSIX 1003.2 (draft 11.3) definition of awk.
You should install mawk if you use awk.