From LQWiki

Character stream manipulation is one of the key points of the UNIX philosophy. It means that you can take the output of a program and pass it as input to another program which, again, produces an output.

Concepts

• piping
• stdout, stderr and stdin
• regex
• ReDirecting
• substitutIon

Commands

• cat
• cut
• tac
• head
• tail
• grep
• wc
• sed
• awk
• xargs
• tr
• paste
• join
• echo
• read
• yes