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Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Validate and pretty-print JSON expressions.
You can use a site like http://www.jsonlint.com/ or use the command line to validate your long and complex json data. This is part of the simplejson package for python http://undefined.org/python/#simplejson. Wrong json expression example: $ echo '{ 1.2:3.4}' | python -m simplejson.tool Expecting property name: line 1 column 2 (char 2)

sum numbers in the file (or stdin)
add integers from the stdin and print out the result usually, cat /tmp/file | echo $(($(tr '\n' '+')0))

Spoof your wireless MAC address on OS X to 00:e2:e3:e4:e5:e6
If you want to check that the spoof worked, type the same command as earlier: $ifconfig en1 | grep ether Now you will see: $ether 00:e2:e3:e4:e5:e6 For the wired ethernet port: $sudo ifconfig en0 ether 00:e2:e3:e4:e5:e6

Emptying a text file in one shot
% = buffer d = delete

generate iso

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Find the cover image for an album
This bash function uses albumart.org to find the cover for an album. It returns an amazon.com url to the image. Usage: albumart [artist] [album] These arguments can be reversed and if the album name is distinct enough, it may be possible to omit the artist. The command can be extended with wget to automatically download the matching image like this: $ albumart(){ local x y="$@";x=$(awk '/View larger image/{gsub(/^.*largeImagePopup\(.|., .*$/,"");print;exit}'

Toggle between directories
switch to previous directory or toggle

How to run a command on a list of remote servers read from a file
dsh - Distributed shell, or dancer?s shell ;-) you can put your servers into /etc/dsh/machines.list than you don't have to serperate them by commata or group them in different files and only run commands for this groups dsh -M -c -a -- "apt-get update"


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