Commands by wwest4 (37)

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commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Periodic Log Deletion
deletes logs not modified in over [#] days - modify to compress or move, as needed

find all active IP addresses in a network
You send a unicast ICMP packet to each host. Many firewalls will drop that ICMP. However, in order to send the ICMP, you'll have first done an ARP request and the remote machine is unlikely to ignore that, so the computer will be in your ARP table.

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"

Uncompress a CSS file
Ever compress a file for the web by replacing all newline characters with nothing so it makes one nice big blob? It is a great idea, however what about when you want to edit that file? ...Serious pain in the butt. I ran into this today in that my only copy of a CSS file was "compressed" with no newlines. I whipped this up and it converted back into nice human readable CSS :-) It could be nicer, but it does the job.

Query Wikipedia via console over DNS
Shorter version, works with multiple words.

View webcam output using mplayer
View webcam output using mplayer, with correct fps and outfmt settings according to my webcam model.

Use vi commands to edit your command lines
If you spend all day editing in vi then switching your fingers to Emacs mode just for the command line can be difficult. Use set -o vi in your bash shell and enjoy the power of a real editor.

In (any) vi, add a keystroke to format the current paragraph.
That goes into your $HOME/.exrc file. " Nice macro to reformat lines: map ^A !}fmt Note that the ^A has to be input by typing ^V^A.

Remove duplicate rows of an un-sorted file based on a single column
$F[0] filters using first word. $F[1] - 2nd, and so on.

Outputs a 10-digit random number


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