explainshell.com - cat a b c %7C grep %27%5Eii%27 %7C awk %27%7Bprint %242%7D%27 %7C sort %7C uniq

a b c %7C grep %27%5Eii%27 %7C awk %27%7Bprint %242%7D%27 %7C sort %7C uniq

concatenate files and print on the standard output

Concatenate FILE(s), or standard input, to standard output.

With no FILE, or when FILE is -, read standard input.

source manpages: cat