Bash: Print Docu from Script Header

When I started to write bash scripts, I used to write a documentation in the script, and write a method to echo another documentation fur the user. It was a bit annoying to have redundant text and keep both up to date. So I wrote below function to print out what I put into the header of the script.

The following is the function I have created for printing out the script header. All the samples on this page where extracted from the MetricCollector. sh script you can find here >> https://github.com/xresch/PENG_Toolbox/blob/master/BashScripts/MetricCollector/metricCollector.sh

############################################################
# Print documentation written in the bash file.
############################################################
print_docu(){

	SOURCE_PATH="${BASH_SOURCE[0]}"

	cat "${SOURCE_PATH}" | gawk ' 
		BEGIN{ 
			isLineInDocumentHead="before";
			print " ";
		}
		
		{
			if ( match($0,"^#############") ){
				
				if ( isLineInDocumentHead == "before" ){
					isLineInDocumentHead="between";
					next;
				}else {
					if ( isLineInDocumentHead == "between"){
						isLineInDocumentHead="end";
					}
				}
				
			}
			
			if ( isLineInDocumentHead == "between"){
				sub("^#","", $0)
				print ;
			}
		}
	'

	exit 1
}

In your script you will write a header like this:

#!/bin/bash
###########################################################################################
# Author: Reto Scheiwiller, 2016
# Licence: MIT License
# Repository: https://github.com/xresch/PENG_Toolbox
#
# Metric Collector
# -----------------
# Collects server and process information from various tools and creates charts with the 
# data. The script was tested on GNU/Linux with gnuplot 4.4.
# For the script to work you have to set the variable "JAVA_HOME" to a valid location.
# All arguments are optional, if "-p" is not used no collections from a process will be done.
#
###########################################################################################

All the text between the two “##########…” lines will get printed, without the leading #. The result will look like this:

Author: Reto Scheiwiller, 2016
Licence: MIT License
Repository: https://github.com/xresch/PENG_Toolbox

Metric Collector
-----------------
Collects server and process information from various tools and creates charts with the 
data. The script was tested on GNU/Linux with gnuplot 4.4.
For the script to work you have to set the variable "JAVA_HOME" to a valid location.
All arguments are optional, if "-p" is not used no collections from a process will be done.

You can add a check if the script has any arguments passed to it, if not you can print out the documentation:

# Check if there is at least one argument present, else print help
if [ "$#" -eq 0 ]
then
	print_docu
fi

Additionally you can add this function to the script options. The following example binds it to the option “-h”:

while getopts "h?" option
do
	case $option in
		h) print_docu;;

		?)  echo "unkown argument: $option";
	esac
done