Uniq

The uniq command in Linux is a command line utility that removes repeated lines in a file or supplied text. In other words the uniq tool helps detect and delete adjacent duplicate lines of text.

For example this command:

awk -F "/" '/^\// {print $NF}' /etc/shells | sort

Will output:

bash
bash
fish
fish
git-shell
sh
sh

If we take that same command and pipe it into uniq:

awk -F "/" '/^\// {print $NF}' /etc/shells | sort | uniq

We get:

bash
fish
git-shell
sh