Say you're poking around a cdrom backup you just popped into your computer. 3 deep in your documents directory you find a list of software you had on your box, say, 8 months ago. If you're anything like me the very first thing you think about when you see this file is to compare it to current. OK, so let's do that.

I have the file open in Geany, because you know I'm doing exactly what I'm writing about. Heh, I just found that file. Anyway, I can see the path in Geany and you'll likely see it right in front of you in your terminal-fu or whichever txt editor you're in. You need the path because you're going to copy (cp) the file to a spot on your hard drive.

Terminal-fu up, and -- make a directory:

• $ mkdir -p stuff/deleteme

Now copy the file you just found to that directory

• $ cp /media/cdrom0/wherever/thatfile ~/stuff/deleteme

Now go into that directory.

• $ cd ~/stuff/deleteme

Now make a new list of installed software.

$ dpkg --get-selections > current-software-18feb11.txt

Now see how they looked stacked side by side.

• $ xxdiff that-file-you-found.txt current-software-18feb11.txt

And there you go. What? A minute? Yeah, that's why it's the wicked.

You will love your terminal-fu.