Question

HI all,

I wrote this code but it doesn’t catch any of the two variables being null, why?

echo "$var1 - $var2"

if [ "$var1" == ""] || [ "$var2" == ""]
then
    echo "Incomplete data"
    exit 1
fi

The initial echo prints nothing for the variables when I run my script so the if statement should work right? But it doesn’t for some reason.

Answer 1

|| has a different meaning in the shell. Also == is not used for comparison; = is. Maybe you meant:

 if [ -z "$var1" -o -z "$var2" ]

Quoting from the manpage:

EXPRESSION1 -o EXPRESSION2
              either EXPRESSION1 or EXPRESSION2 is true

-z STRING
              the length of STRING is zero