Creating a library of functions

If we want to create our own library of functions, then we can create a script and add all the functions into this script. We can make all the functions from our script functions.sh available in the current shell by calling source or the period . command.

The procedure to load all functions into the current shell is as follows:

$ countryUSA

Since the function country is not a part of the shell environment, this command will give an error:

$ . functions.sh

Or:

$ source functions.sh
$ country USA India Japan

This will execute the function country along with the parameter USAIndia Japan.

We can even load a script containing library functions inside another script as follows:

#!/bin/bash
. /../my-library.sh
call_library_functions();

We have called the library function script my-library.sh inside another script. This will define all the functions within the script my-library.sh available in the current script environment.