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Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

Colored status of running services
Replace service --status-all 2>&1 by service --status-all 2>/dev/null to hide all services with the status [ ? ]

Get Hardware UUID in Mac OS X
Formats the output from `ioreg` into XML, then parses the XML with `xmllint`'s xpath feature.

execute a shell with netcat without -e
how to execute a shell on a server with a netcat binary which doesn't support -e option

Make a file not writable / immutable by root
http://linuxhelp.blogspot.com/2005/11/make-your-files-immutable-which-even.html

Find the package that installed a command

Pick a random image from a directory (and subdirectories) every thirty minutes and set it as xfce4 wallpaper
Change your wallpaper every thirty minutes (or however long you like, I suppose) to a randomly selected image in a directory and subdirectories. Bear in mind this is not safe to use if anyone else has write access to your image directory.

parse and format IP:port currently in listen state without net tools
Useful for containers and environments where you need to know if a port is currently in listen mode but you have not easy way or privileges to install net-tools like netstat or ss. "0A" is the code for listen state. The IP hex is reverse order and all in hex format.

Cryptographically secure 32-bit RNG in strict ZSH
ZSH ships a couple random number generators via the $RANDOM environment variable and rand48() via zsh/mathfunc, but neither are cryptographically secure. This code produces a 32-bit random number suitable for cryptography. It's only dependency is /dev/urandom and it does not rely on any shell commands or 3rd party utilities. It assumes ZSH was compiled with 64-bit integer support.

Easy to extend one-liner for cron scripts that automate filesystem checking
This one-liner is for cron jobs that need to provide some basic information about a filesystem and the time it takes to complete the operation. You can swap out the di command for df or du if that's your thing. The |& redirections the stderr and stdout to the mail command. How to configure the variables. TOFSCK=/path/to/mount FSCKDEV=/dev/path/device or FSCKDEV=`grep $TOFSCK /proc/mounts | cut -f1 -d" "` MAILSUB="weekly file system check $TOFSCK "


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