Normally, whenever we enter a command, the new process gets created. If we want to make functions from the script to be made available in the current shell, then we need a technique that will run the script in the current shell instead of creating a new shell environment. The solution to this problem is using either the source or . commands.
The commands, source and ., can be used to run the shell script in the current shell instead of creating a new process. This helps with declaring functions and variables in the current shell.
The syntax is as follows:
$ source filename [arguments]
Or you can use the following:
$ . filename [arguments] $ source functions.sh
Or you could use this:
$ . functions.sh