Local and Environment Variables

Variables are prefixed by a dollar sign ($). A value is assigned to a variable through an equals sign (=) (no whitespace on either side of it).

MY_VARIABLE='my value'
echo $MY_VARIABLE

By default, variables are seen only within the shell itself. To pass variables to other programs invoked within the shell, they have to be exported to the environment.

set

Display ot set shell variables.

printenv

Display environment variables.

env

Run a program in a modified environment.

export

Export a local variable to the environment.