check if variable is empty bash code example
Example 1: bash if null or empty
if [ -z "$variable" ];
then echo "$variable is null";
else echo "$variable is not null";
fi
Example 2: bash if variable is not empty
VAR=`echo Hello world`
if [[ -n "$VAR" ]] ; then echo "Variable is set" ; fi
Example 3: bash check if variable is empty
if [ -z "$var" ] #return true if $var is unset