Boy oh boy, where to begin with grep. This one took me down a rabbit hole. grep is one of those tools that I feel has always been there; like with ls and cd. It is a command I’ve come to rely on for almost anything I do on the command line. I will say this, grep is powerful, like SUPER powerful. It’s so vast and complex that people have written multiple books about it. So before we dive in, remember that this is an overview. It won’t cover everything, because I cant. But I hope to give you some building blocks to which you can use to build greater things.

What a great name for a tool. Funny enough, there is a dog command, but it’s not installed by default. The original cat came with Unix version 1 in November 1971, and it replaced an older command called pr. Believe it or not, chances are, the pr command is on your machine today! That’s a new one on me. The pr command has a different output format than cat, making it a bit “prettier” because it offers a pagination filter. Anyway, back to cat…

As with chmod, this is another program that has stood the test of time…Unix time ba dum tsh. This was also another command that was released with Unix 1, and the GNU version was released as part of Fileutils in October 1992. The chown command stand for change owner. As you may have guessed, it allows one to change the owner of a file or directory, and allows you to change the group as well.

This is one of the oldest commands as it has been around since the first version of Unix that was released in 1971. The GNU version was written by David MacKenzie, the same author as head, tail, and many others that I haven’t covered yet. chmod stands for change mode. What some may consider to be file permissions were considered modes, and are still referenced as such.

Like all great Unix commands, top has a meaning behind its name. It stands for Table Of Processes. Not surprising as it shows a wealth of information running about the system. If you’re running a Linux machine, or macOS (or some BSD variant), top is an extremely useful program. It is a task manager, err..well, more of a system monitor, but has some task manager like properties. The original program was first released in 1984 by William LeFebvre for Unix.

Probably should have done this in opposite order, as a precursor to the uniq command. But who cares. If you’ve follwed yesterday’s post, then you’ve had some exposure to the sort command. Let’s dive into it and get some more use out of it!

Finding uniquiness in a list! Remove duplicates, print duplicated, show only duplicates…the possibilities are endless! Well, actually there is a finite number of posibilities, but that involves combinatorics. And I’m too lazy for that right now. Anyway… uniq is pretty slick. Check it out!

If you saw yesterday’s Command of the Day about head then you prolly saw this coming.