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What is my ip?

An alias to select a portion of your desktop and save it as an image.

tar the current directory wihtout the absolute path
tars the current directory (and its children) in an archive of the same name (plus ".tar" :)) in the parent directory without the absolute path, so that when the archive is extracted, only the current directory name is created for the path. Assumes bash/zsh.

Remove leading zeros in multiple columns with sed
Leading zeros might help correct sorting and they can be removed by sed after sorting

get delicious bookmarks on your shell (text version :-))
a variation of avi4now's command - thanks by the way!

check open ports (both ipv4 and ipv6)

Generate a random password 30 characters long
According to the gpg(1) manual: --gen-random 0|1|2 count Emit count random bytes of the given quality level 0, 1 or 2. If count is not given or zero, an endless sequence of random bytes will be emitted. If used with --armor the output will be base64 encoded. PLEASE, don't use this command unless you know what you are doing; it may remove precious entropy from the system! If your entropy pool is critical for various operations on your system, then using this command is not recommended to generate a secure password. With that said, regenerating entropy is as simple as: $ du -s / This is a quick way to generate a strong, base64 encoded, secure password of arbitrary length, using your entropy pool (example above shows a 30-character long password).

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"

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

Printout a list of field numbers (awk index) from a CSV file with headers as first line.
Useful to identify the field number in big CSV files with large number of fields. The index is the reference to use in processing with commands like 'cut' or 'awk' involved.


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