UNIX & Linux Pipes & Utilities - tr, cut, sort, egrep
Creating UNIX & Linux Piped Commands
UNIX and Linux offer a very powerful feature know as pipes. It is often possible to carry out really complicated tasks without the need for shell scripting, variables, loops, etc.
Take the following example, which creates a dictionary file from a text document, but excludes one and two letter words:
tr -cs "[a-z][A-Z]" "[\012*]" < readme.txt | sort -uf | tr "[A-Z]" "[a-z]" | egrep -v "(^.$|^..$)" > dictionary
One command line that is comprised of five separate steps: