Testing setting environment variables in bash

README.md

Running ./test.sh gives the below output:

test1 is empty
test2 is set (empty string)
test3 is set (has string though)
test4 is not set (does not exist at all)

test.sh

#!/bin/bash

set -eu

TEST1=""

if [[ "${TEST1}" != "" ]]; then
  echo 'test1 is NOT empty'
else
  echo 'test1 is empty'
fi

TEST2=""

if [[ -z "${TEST2+x}" ]]; then
  echo 'test2 is not set'
else
  echo 'test2 is set (empty string)'
fi

TEST3="something"

if [[ -z "${TEST3+x}" ]]; then
  echo 'test3 is not set'
else
  echo 'test3 is set (has string though)'
fi

if [[ -z "${TEST4+x}" ]]; then
  echo 'test4 is not set (does not exist at all)'
else
  echo 'test4 is set'
fi