In Unix there are many Filter commands like- cat, awk, grep, head, tail cut etc.
A Filter is a software program that takes an input and produces an output, and it can be used in a stream operation.
E.g. cut -d : -f 2 /etc/passwd | grep abc
We can mix and match multiple filters to create a complex command that can solve a problem.
Awk and Sed are complex filters that provide fully programmable features.
Even Data scientists use Unix filters to get the overview of data stored in the files.