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Big (four-byte) $RANDOM
Sometimes, in a shell script, you need a random number bigger than the range of $RANDOM. This will print a random number made of four hex values extracted from /dev/urandom.

convert Decimal to IP from stdin
https://stackoverflow.com/questions/10768160/ip-address-converter

start a VNC server for another user

Leap year calculation

Send a local file via email
Another way of sending an attachment. -s : subject file : file to be sent

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"

Filter IP's in apache access logs based on use
Show's per IP of how many requests they did to the Apache webserver

Download Englishword pronounciation as mp3 file

Check if a machine is online
PING parameters c 1 limits to 1 pinging attempt q makes the command quiet (or silent mode) /dev/null 2>&1 is to remove the display && echo ONLINE is executed if previous command is successful (return value 0) || echo OFFLINE is executed otherwise (return value of 1 if unreachable or 2 if you're offline yourself). I personally use this command as an alias with a predefined machine name but there are at least 2 improvements that may be done. Asking for the machine name or IP Escaping the output so that it displays ONLINE in green and OFFLINE in red (for instance).

Print a monthly calendar with today's date highlighted
The cal command is handy, but sometimes you want to quickly see today's date highlighted. That's why I came up with this quick command. Much like http://www.commandlinefu.com/commands/view/1342/show-this-months-calendar-with-todays-date-highlighted but cleaner and more succinct.


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