Commands by frozenfire (4)

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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"

Reducing image size
Adding the exclamation mark to the image geometry ignores the original aspect ratio. More info about image geometry: http://www.imagemagick.org/script/command-line-processing.php#geometry

Do quick arithmetic on numbers from STDIN with any formatting using a perl one liner.
Good for summing the numbers embedded in text - a food journal entry for example with calories listed per food where you want the total calories. Use this to monitor and keep a total on anything that ouputs numbers.

List the Sizes of Folders and Directories

Adding Prefix to File name
Good old bracket expansion :-) For large numbers of files, "rename" will spare you the for-loop, or the find/exec...

Stoppable sleep
A nice way to interrupt a sleep with a signal.

duration of the DNS-query

Find usb device
I often use it to find recently added ou removed device, or using find in /dev, or anything similar. Just run the command, plug the device, and wait to see him and only him

Verify MD5SUMS but only print failures
All valid files are withheld so only failures show up. No output, all checks good.

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.


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