UNIX for Dummies Questions & Answers

Hi

I'm trying to ensure that I have catered for all situations with my getopt cases.

One other situation I want to cover is should the user enter the script without any preceding arguments eg:

Code:

./script_eg

I need the script to the direct the user to the helpfile

I have tried this:

Code:

while getopts " i: p: o: n: h " option
do
case $option in
i ) id="$OPTARG";;
p ) paramval="$OPTARG";;
o ) oldfile="$OPTARG";;
n ) newfile="$OPTARG";;
h ) displayHelp;exit;;
? ) displayHelp;exit;;



esac;
done

the "?" only directs the user to the helpfile if the user enters anything other than the listed arguments for eg:

Code:

./script_eg -s

since s is not listed as one of my arguments, it directs me to the helpfile.

what will cater for whitespaces or null values?

getopt doesn't handle white space, however all is not lost.

just change you script and insert a line checking for arguments or lack thereof:

Code:

[[ $# -eq "0" ]] && displayHelp

while getopts " i: p: o: n: h " option

Note: you would want an exit at end of your displayHelp function, so it exits cleanly after displaying your help message(s).

Safest bet is that you don't leave it up to run-time. You define all vars ahead of the getopts section of your code, which your other posts seem to suggest you've done already. getopts is only going to rely on the case..esac statement.

Further safeguards would be to explicitly fall back to your earlier variable value:

Code:

myarg="${1:-myarg}"

Likewise, since the -s switch shown isn't in your case..esac statement, you'd accommodate this by making your last entry as follows:

Code:

while getopts " i: p: o: n: h " option
do
case $option in
i ) id="$OPTARG";;
p ) paramval="$OPTARG";;
o ) oldfile="$OPTARG";;
n ) newfile="$OPTARG";;
h | ? | * ) displayHelp;exit;;

esac;
done

This forces bum switches into the usage statement you've already defined.

Thank u so much. This works perfectly