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Display the definition of a shell function
Display the code of a previously defined shell function.

a function to create a box of '=' characters around a given string.
The function 'box' takes either one or two arguments. The first argument is a line of text to be boxed, the second argument (optional) is a character to use to draw the box. By default, the drawing character will be '='. The function 'n()' is a helper function used to draw the upper and lower lines of the box, its arguments are a length, and an character to print. (I used 'n' because 'line', 'ln' and 'l' are all commonly used)

Who has the most Apache connections.
This will tell you who has the most Apache connections by IP (replace IPHERE with the actual IP you wish to check). Or if you wish, remove | grep -c IPHERE for the full list.

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"

Set file access control lists
The file myfile is owned by tom and has read and write permissions for tom. Group and other permissions are empty which make myfile readable and writable only by tom. setfacl enables user tom to give read permission to user john only. The command 'ls -l' shows a '+' sign telling us that file access control list has been setup for myfile.

Test your bash skills.

find which lines in a file are longer than N characters
Filter out lines of input that contain 72, or fewer, characters. This uses bash only. ${#i} is the number of characters in variable i.

Testing reading speed with dd

Go up multiple levels of directories quickly and easily.
Change to your taste. Much quicker than having to add 'cd' every time. Add it to your .bashrc or .bash_profile.

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


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