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convert ascii string to hex
You can use "decode()" in a similar manner: $ python -c 'print "68656c6c6f".decode("hex")'

Comparison between the execution output of the last and penultimate command
Useful for checking if there are differences between last and penultimate command.

Determine if a port is open with bash
For times when netcat isn't available. Will throw a Connection refused message if a port is closed. Scriptable: $ (: /dev/null && echo "OPEN" || echo "CLOSED"

Swap a file or dir with quick resotre
This lets you replace a file or directory and quickly revert if something goes wrong. For example, the current version of a website's files are in public_html. Put a new version of the site in public_html~ and execute the command. The names are swapped. If anything goes wrong, execute it again (up arrow or !!).

Check if your desired password is already available in haveibeenpwnd database. This command uses the API provided by HIBP

A Console-based Audio Visualizer for ALSA
# Installing apt search cava sudo apt install cava # modify the default config to change the colors by their hex color code cava -p mkdir ~/.cava nano ~/.cava/config cava # run with changes!

Emulate tail using awk.
This awk codes emulates tail. For efficiency it uses a circular array, which stores only N number of records. Using awk gives the flexibility of modifying the output as needed, for example adding the record number (NR) at the output and much more.

Create backup copy of file, adding suffix of the date of the file modification (NOT today's date)

Copy ssh keys to user@host to enable password-less ssh logins.
To generate the keys use the command ssh-keygen

online MAC address lookup


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