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Check if a command is available in your system
Usefull to detect if a commad that your script relies upon is properly installed in your box, you can use it as a function function is_program_installed() { type "$1" >/dev/null } Invoke it and check the execution code is_program_installed "dialog" if [ ! $? -eq 0 ]; then echo "dialog is not installed" exit 1 fi

Faster find and move using the find and xargs commands. Almost as fast as locate.
Only tested on Linux Ubunty Hardy. Works when file names have spaces. The "-maxdepth 2" limits the find search to the current directory and the next one deeper in this example. This was faster on my system because find was searching every directory before the current directory without the -maxdepth option. Almost as fast as locate when used as above. Must use double quotes around pattern to handle spaces in file names. -print0 is used in combination with xargs -0. Those are zeros not "O"s. For xargs, -I is used to replace the following "{}" with the incoming file-list items from find. Echo just prints to the command line what is happening with mv. mv needs "{}" again so it knows what you are moving from. Then end with the move destination. Some other versions may only require one "{}" in the move command and not after the -I, however this is what worked for me on Ubuntu 8.04. Some like to use -type f in the find command to limit the type.

Detach a process from the current shell
Continue to execute the command in background even though quitting the shell.

Release memory used by the Linux kernel on caches
The Linux kernel uses unused memory in caches. When you execute "free" you never get the "real" available memory.

Filter IP's in apache access logs based on use
Show's per IP of how many requests they did to the Apache webserver

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Calculate sum of N numbers (Thanks to flatcap)

Remove all the files except abc in the directory
Finds all files in the current directory and deletes them besides file called "abc"

Compute newest kernel version from Makefile on Torvalds' git repository
The platform-agnostic version of https://www.commandlinefu.com/commands/view/25276/compute-newest-kernel-version-from-makefile-on-torvalds-git-repository because macOS doesn't have wget installed

Show number of NIC's, ports per nic and PCI address


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