All commands

These days, most software distributed in tar files will just contain a directory at the top level, but some tar files don't have this and can leave you with a mess of files in the current folder if you blindly execute

This command can help you clean up after such a mistake. However, note that this has the potential to do bad things if someone has been *really* nasty with filenames.

The "vorbiscomment" utility lets you update information such as artist names and song and album tags in an Ogg Vorbis file. You can use this command to fix any mistakes that were made when ripping an album.

Yet another ps grep function, but this one includes the column headings.

The $[...] block in bash and zsh will let you do math.

This is the same as using $((...)), which also works in ksh. Of course, this is a simple, dumb wrapper and doesn't allow floating-point.

MIME::Base64 is a part of Perl5 distribution. You can also use decode_base64 for oposite result.

Upgraded Debian/Ubuntu/etc. systems may have a number of "orphaned" packages which are just taking up space, which can be found with the "deborphan" command. While you could just do "dpkg --purge $(deborphan)", the act of purging orphans will often create more orphans. This command will get them all in one shot.

Use gstreamer to capture v4l2:///dev/video0 and show ascii art video in display.

Enter your ssh public key in the remote end for future key-based authentication. Just type your password one last time. The next time you should be able to login with the public key. If you don't have a key, generate one with ssh-keygen.

Requires Bourne-compatible shell in the remote end.

Loads your CPU, run a instance for each CPU/CORE.

self explanatory see sample output

This command will generate white noise through your speakers (assuming you have sound enabled). It's good for staying focused, privacy, coping with tinnitus, etc. I use it to test that the sound works.

While copying a large file that may take up a good chunk of your hard drive, start the copy and run this command concurrently. It will print out the disk information every second. It's pretty handy when you have a large copy with nothing to monitor the progress.

This will convert filenames from uppercase to lowercase. I find this useful after downloading images from my digital camera. This works for English, but other languages may need something slightly more complex like this:

Also, the quote marks aren't necessary if your filenames don't contain spaces.

Windows

I have this on a daily cronjob to backup the commandlinefu.com database from NearlyFreeSpeech.net (awesome hosts by the way) to my local drive. Note that (on my Ubuntu system at least) you need to escape the % signs on the crontab.