Learning Linux Shell Scripting - Second Edition

Command source and period (.)

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
  

If ...