HPR4747: UNIX Curio #13 - Replacements for cat

This series is dedicated to exploring little-known—and occasionally useful—trinkets lurking in the dusty corners of UNIX-like operating systems.

Thirteen is one of my favorite numbers, so I am going to use this episode to indulge myself. As part of UNIX Curio #8 (

HPR episode 4657

), I went on a little flight of fancy and suggested that the

comm

utility could be used in place of

cat

. On further reflection, I realized that there are quite a few utilities that can do that job, almost. This episode is the result of me investigating how many possible ways there are to replace that functionality with standard utilities. Imagine that some prankster has deleted the

cat

utility from your machine, and you need a way to restore that capability without re-installing it.

I should warn you that as opposed to the rest of the series, this episode will not focus heavily on obscure tools, and it is unlikely the examples given will be very useful. Also, I am not going to dive into the history of any of these commands. However, you might still learn something, and it could be a little entertaining to hear about the ways some utilities can be twisted to this purpose.

Let's start by reviewing what the