Question

I am new in shell script, trying to catch the return value of a program, and do something with it.

I have this script below

#!/bin/sh


if [ $# !=2 ] ; then
        echo "Usage : param1 param2 "
        exit 1;
elif [ $# -eq 2 ]; then
        ./callprogram
        $out = $?
        echo "$out"
fi

if [ $out==0 ]; then
    echo "out ok"
fi

It keeps getting me error of

"[: 11: 0: unexpected operator

out ok

I have no clue why line 11 is wrong. if I remove “fi”, it will promt that it needs “fi”. Can anyone help with this matter?

Thank you

Answer 1

You need a space after the [ and you need to use -eq (equals) or -ne (not equals) to compare numbers in your if-statement.

To assign a variable use out=$?, not $out = $?. There should be no spaces on either side of the = sign.

Try this:

if [ $# -ne 2 ] ; then
        echo "Usage : param1 param2 "
        exit 1
elif [ $# -eq 2 ]; then
        ./callprogram
        out=$?
        echo "$out"
fi

if [ $out -eq 0 ]; then
    echo "out ok"
fi