Shell Programming and Scripting

hello there I am back with more questions (sorry it is been quite a while since I had done scripting). I had tried the search function to search for the threads that might have an answer to my question, but I could not find it, so I had decided to post it.

I had created the scripts below in ksh (assume the ksh file name is abc.ksh)
--------------------------------------------------------------------------
var1=' '
var2=' '

while getopts ":a" opt
do
case $opt in
a) var1=$OPTARG;;
b) var2=$OPTARG;;
\?) echo "Invalid argument"; exit 1;;
esac
done
shift 'expr ${OPTIND} - 1'

echo "Statement"
--------------------------------------------------------------------------

I ran the codes
--------------------------------------------------------------------------
Server temp-> abc.ksh -a some_value -b other_value
--------------------------------------------------------------------------

It works perfect, but if I ran the code with out the command line option
--------------------------------------------------------------------------
Server temp-> abc.ksh some_value other_value
Statement
--------------------------------------------------------------------------

I thought if there are no -a or -b option is given, getopts would automatically faults out and abc.ksh would just display "Invalid Argument" and exit. Did I not doing this section of scripts correctly or I am just plain missing something?

Thank you for your time

It would fault out if you entered abc.ksh -c somevalue
because c is not in the choices getopts has. It only checks characters like -<character>

You can use $# to return the number of command line arguments, so for example,

Code:

if [[ $# -lt 3 ]] ; then
   echo "Invalid arguments"
   exit 1
fi

Change the 3 above into whatever number you want.
[/code]

yes that would work, but the thing what if my users forgot to use the options, such as just using it as "abc.ksh some_value". Because I thought I had set the error at the last line, when "abc.ksh" is call without options, it would return invalid argument and exit. But it had executed the next instruction instead.

For example if I execute the abc.ksh without using command line option,
--------------------------------------------------------------------------
Server temp-> abc.ksh some_value other_value
--------------------------------------------------------------------------

I would expect the folloing output
--------------------------------------------------------------------------
Invalid argument
--------------------------------------------------------------------------

Instead I got the following
--------------------------------------------------------------------------
Statement
--------------------------------------------------------------------------

I was thinking to use this abc.ksh with options, if user did not key in the correct option, I would only print the error as well as the usage and then exit the abc.ksh. But when I executed this scripts, if user start using this without the correct option, it still execute the next line then exit.

So I am wondering if I had messed up my logic or I did not use this option correctly.