Commands by Vasudev (4)

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Set RGB gamma of secondary monitor
This command first determines whether a second screen is connected. If this is the case, it sets the screen's RGB gamma via xrandr. Useful for cheap or slightly defective monitors with a tint. In this example a yellowing/champagne color deviation is compensated for by decreasing the red and the green portion of the image.

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"

Print a list of all hardlinks in the working directory, recursively
libpurple likes to hardlink files repeatedly. To ignore libpurple, use sed: | sed '/\.\/\.purple/d'

Rename a file with a random name
Give files a random name (don't ask why :-) The function will rename files but maintain their extensions. BUG: If a file doesn't have an extension it will end up with a dot at the end of the name. The parameter '8' for pwgen controls the length of filenames - eight random characters.

Easily find latex package documentation
If the pdf/dvi/etc documentation for a latex package is already part of your local texmf tree, then texdoc will find and display it for you. If the documentation is not available on your system, it will bring up the package's webpage at CTAN to help you investigate.

resize all JPG images in folder and create new images (w/o overwriting)
Convert all jpegs in the current directory into ~1024*768 pixels and ~ 150 KBytes jpegs

Prevent non-root users from logging in
Also with optional message: $ echo "no login for you" > /etc/nologin (This doesn't affect your current X session - you're already logged in!)

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Getting the ip address of eth0

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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