Shell Programming and Scripting

How do I get the getopts command to display whats written at my help option if no option is types in? For example,

Code:

myscript.sh -h

will bring up my help option, however, I also want

Code:

myscript.sh

to do the same!

Code:

#!/bin/bash
 
while getopts :abh opt
 
do case "$opt" in
a)flag="today";;
b)flag="yesterday";;
h)echo "please enter an option; -a for today, and -b for yesterday";;
[?])echo "Unknown option";;
 
esac
done
 
echo "Hello world"

This works if I type in a wrong option such as -j, where it tells me its an "unknown option" but if I do no option, so just myscript.sh, it prints hello world straight away.

One way (at the top of the script).

Code:

if [ $# -eq 0 ]
then
        echo "please enter an option; -a for today, and -b for yesterday"
        exit
fi

Yep that good!! Thanks!