Linux/Environment Variables

Basics

• List all environment variables

env
printenv

• get variable

echo $USER
printenv USER

• set variable

VARIABLE='Hello world'
echo $VARIABLE

• promote a shell variable to an environment variable

export VARIABLE='Hello world'

• variable lists

VARIABLE='Hello world':'test'    # variable with two elements
VARIABLE=$VARIABLE:'test2'       # add another element

• remove variable

unset VARIABLE

Use in scripts

• script.sh

DATE='01-01-2000'
export DATE
export VARIABLE="123"

• load variables from .env file and export them

set -o allexport
source .env set
set +o allexport