Download YouTube videos as .flv and convert them to .3gp for your mobile phone.

Use ImageMagick to create a "black and white" copy of an image.

Example: To store the function addfunction after you have defined it:

An alias i made for myself to play music in a faster way.

Works great when you have Guake / Tilda installed (Console that drops down like in the game QUAKE)

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I put this in my bash_alias file (I'm on ubuntu, the bash_alias file does autostart with the right config) but it works putting it in bashrc too. Or anything that autostarts when the console is opened.

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Needs Mplayer and music files to work. With out music theres nothing to play!

Oh, and also, without modification, this alias will try to play stuff from your ~/Music folder! (case sensitive). Make sure that folder exists and has music OR edit this alias to fit your needs.

When playback of AVI files (containing a video format like XviD or DivX) is stuttering, it in 90% of the files is caused by a poorly or wrongly interleaved file. The issue can be permanently resolved by RE-MUXING the AVI video-files that have this problem

vim will open both files side by side and show colored diffs

Cheese or other webcam software not working? Try this.

If you want to operate on a set of items in Bash, and at least one of them contains spaces, the `for` loop isn't going to work the way you might expect. For example, if the current dir has two files, named "file" and "file 2", this would loop 3 times (once each for "file", "file", and "2"):

Instead, use a while loop with `read`:

After a command is run in bash, !$ is set to the last (space-delimited) argument of the command. Great for running several commands against the same file in a row.

Creates a zip file out of each subdirectory in a directory. Great if you have 40 000+ text files in folders, and you want to stick it in SVN without the hours of uploading while retaining some level of version control.

It extracts X number of lines from file1 and dumps them to file2.Using grep with the empty string '' extracts the complete lines (i.e. no filtering takes place) and the -m flag indicates how many lines to extract out from the given file. Then using the redirect > operator we send the extracted lines to a new file.

The brace expansion also allows you to count backward:

for i in {15..1}; do echo $i; done

You can also use this construct to create new file or new directory:

mkdir dir{1..3} # Same as mkdir dir1 dir2 dir3

This loops through all tables and changes their collations to UTF8. You should backup beforehand though in case some data is lost in the process.

Useful for monitoring both MySQL and the server load at the same time.

Displays the duplicated lines in a file and their occuring frequency.

Autojump is cd command that learns. More info: http://wiki.github.com/joelthelion/autojump

Show the number of failed tries of login per account. If the user does not exist it is marked with *.

Replace "url" with the correct address of what your're downloading. Replace 01:00 with what time you want. (24-hour clock).

Displays all information about your battery. for just capacity, try replacing cat with

Battery number might be BAT0 instead of BAT1. Just run

and find out what folder is in that directory and replace that name with BAT1

I often deal with long file names and the 'ls -l' command leaves very little room for file names. An alternative is to use the -h -o and -g flags (or together, -hog).

* The -h flag produces human-readable file size (e.g. 91K instead of 92728)

* The -o suppresses the owner column

* The -g suppresses the group column

Since I use to alias ll='ls -l', I now do alias ll='ls -hog'