check if not empty shell code example

Example 1: bash check if variable is empty

if [ -z "$var" ] #return true if $var is unset

Example 2: shell cehck if string is null

my_var="nixCraft"
if [ -z "$my_var" ]
then
      echo "\$my_var is NULL"
else
      echo "\$my_var is NOT NULL"
fi

// https://www.cyberciti.biz/faq/bash-shell-find-out-if-a-variable-has-null-value-or-not/