All commands

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.

My variant on this common function. Some highlights:

Allows you to override the default ps args of "aux"

Uses bracket trick to omit the grep process itself without having to use a second grep

Always prints the correct header row of ps output

Limitations: Ugly ps error output if you forget to quote your multi word grep argument

It is a pain grep-ing/sed-ing/awk-ing plain old df. POSIX it!

The expansion {,} in bash will repeat the given string once for each item seperated by commas. The given command will result in the following being run:

cp /really/long/path/and/file/name /really/long/path/and/file/name-`date -I`

These can be embedded as needed, ex: rm file{1,2,3{1,2,3}} would delete the files file1, file2, file31, file32, file32, and no other files.

Countdown from 10 or whatever you want:)

trap is the bash builtin that allows you to execute commands when the current script receives a particular signal.

Uses $0 for the script name, $$ for the script PID, tee to output to STDOUT as well as a log file and ps to log other running processes.