Linux Batch Prepend Header File to Series of Files

Have you ever been in a position where you need to prepend a header file to a series of other files? Typically, if you have created a series of program files and needed to add a standard copyright notice at the top of every file in the suite, then this would be the case.

Below is a method of achieving exactly this. We are going to use the UNIX tac command line utility (cat backwards!) to achieve this, and use a shell script for statement to loop though each file in the directory.

The basic syntax will be:

tac program_file prepend_file | tac > new_file

Now for my example, I have two areas within my bookcat Drupal module directory structure containing my source files - includes/templates and includes/classes. I will copy the entire directory tree to a temporary area, then run the script below which will add the necessary headers.