Today I had to script a bit inside a Linux VM on Azure. I had to make some test inside a bash script. To my extent I’am not a Linux expert, but I wanted to share a small tip I found.
How to find is a variable is empty or unset in BASH ?
To find if a variable is SET to empty to a “” string please use the comand :
if [ -z “$VAR” ];
Another way to write it would be with double bracket :
if [[ -z $var ]]
if [[ -z “$var” ]]
if [[ ! $var ]]
if [[ ! “$var” ]]
or that expression would check if it’s with a value :
if [[ $var ]]
Thanks everyone, enjoy the small tip