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.Read the full book at www.amazon.com