Define a function vert () { echo $1 | grep -o '.'; } Use it to print some column headers paste <(vert several) <(vert parallel) <(vert vertical) <(vert "lines of") <(vert "text can") <(vert "be used") <(vert "for labels") <(vert "for columns") <(vert "of numbers") Show Sample Output

no loop, only one call of grep, scrollable ("less is more", more or less...)

Proper screencast with audio using ffmpeg and x264, as per http://verb3k.wordpress.com/2010/01/26/how-to-do-proper-screencasts-on-linux/

This command uses ping to get the routers' IP addresses to the destination host as traceroute does. If you know what I mean..

..not guaranteed to always be accurate but fun to see how old you Linux installation is based on the root partitions file system creation date. Show Sample Output

It identifies the parents of the Zombie processes and kill them. So the new parent of orphan Zombies will be the Init process and he is already waiting for reaping them. Be careful! It may also kill your useful processes just because they are not taking care and waiting for their children (bad parents!). Show Sample Output

My key is the anonymous one, is good for 50 post an hour with a maximun number of uploads a day, probably will run out, if that happend you can get a free key at the site. Show Sample Output

Surround the first letter of what you are grepping with square brackets and you won't have to spawn a second instance of grep -v. You could also use an alias like this (albeit with sed): alias psgrep='ps aux | grep $(echo $1 | sed "s/^\(.\)/[\1]/g")'

doesn't do case-insensitive filenames like iname but otherwise likely to be faster

I needed a way to search all files in a web directory that contained a certain string, and replace that string with another string. In the example, I am searching for "askapache" and replacing that string with "htaccess". I wanted this to happen as a cron job, and it was important that this happened as fast as possible while at the same time not hogging the CPU since the machine is a server. So this script uses the nice command to run the sh shell with the command, which makes the whole thing run with priority 19, meaning it won't hog CPU processing. And the -P5 option to the xargs command means it will run 5 separate grep and sed processes simultaneously, so this is much much faster than running a single grep or sed. You may want to do -P0 which is unlimited if you aren't worried about too many processes or if you don't have to deal with process killers in the bg. Also, the -m1 command to grep means stop grepping this file for matches after the first match, which also saves time. Show Sample Output

Simply more email-adresses matched Show Sample Output

similar to the previous command, but with more friendly output (tested on linux)

Not as taxing on the CPU.

This Anti-TarBomb function makes it easy to unpack a .tar.gz without worrying about the possibility that it will "explode" in your current directory. I've usually always created a temporary folder in which I extracted the tarball first, but I got tired of having to reorganize the files afterwards. Just add this function to your .zshrc / .bashrc and use it like this; atb arch1.tar.gz and it will create a folder for the extracted files, if they aren't already in a single folder. This only works for .tar.gz, but it's very easy to edit the function to suit your needs, if you want to extract .tgz, .tar.bz2 or just .tar. More info about tarbombs at http://www.linfo.org/tarbomb.html Tested in zsh and bash. UPDATE: This function works for .tar.gz, .tar.bz2, .tgz, .tbz and .tar in zsh (not working in bash): atb() { l=$(tar tf $1); if [ $(echo "$l" | wc -l) -eq $(echo "$l" | grep $(echo "$l" | head -n1) | wc -l) ]; then tar xf $1; else mkdir ${1%.t(ar.gz||ar.bz2||gz||bz||ar)} && tar xf $1 -C ${1%.t(ar.gz||ar.bz2||gz||bz||ar)}; fi ;} UPDATE2: From the comments; bepaald came with a variant that works for .tar.gz, .tar.bz2, .tgz, .tbz and .tar in bash: atb() {shopt -s extglob ; l=$(tar tf $1); if [ $(echo "$l" | wc -l) -eq $(echo "$l" | grep $(echo "$l" | head -n1) | wc -l) ]; then tar xf $1; else mkdir ${1%.t@(ar.gz|ar.bz2|gz|bz|ar)} && tar xf $1 -C ${1%.t@(ar.gz|ar.bz2|gz|bz|ar)}; fi ; shopt -u extglob} Show Sample Output

Backups all MySQL databases to individual files. Can be put into a script that grabs current date so you have per day backups.

Very useful set of commands to know when your file system was created. Show Sample Output

grep -o puts each occurrence in a separate line

Adapted using your usefull comments !

This will calculate the your commandlinefu votes (upvotes - downvotes). Hopefully this will boost my commandlinefu points. Show Sample Output

mixing tabs and spaces for indentation in python would confuse the python interpreter, to avoid that, check if the file has any tab based indentation. "^V" => denotes press control + v and press tab within quotes. cat improper_indent.py class Tux(object): print "Hello world.." grep " " improper_indent.py print "Hello world.."