coreutils: The sort command
The ‘sort’ Command
==================
Next we’ll look at the ‘sort’ command. This is one of the most powerful
commands on a Unix-style system; one that you will often find yourself
using when setting up fancy data plumbing.
The ‘sort’ command reads and sorts each file named on the command
line. It then merges the sorted data and writes it to standard output.
It will read standard input if no files are given on the command line
(thus making it into a filter). The sort is based on the character
collating sequence or based on user-supplied ordering criteria.