Variables

Assigning Variables

var=1
echo $var # var is the variable, $var is the value

N:B:

• Do not confuse this with = and -eq, which test, rather than assign! so ... var = 1 won't work. Mind the Gap!!!

• Bash Variables Are Untyped

• To expose the variable to sub-processes use export.

$ export foo="Hello, World"
$ bar="Goodbye"

$ echo $foo
Hello, World
$ echo $bar
Goodbye

$ bash
bash-3.2$ echo $foo
Hello, World
bash-3.2$ echo $bar

bash-3.2$ 

Shell Variables

variable	Meaning
$0
$?	Exit code from last command
$1 $2 $3 and so on	1st 2nd 3rd parameters and so on
$SHELL	The Shell
$HOME	User Home directory
$USER	Shell Username

Shell Variable declaration

• declare
• export
• set
• let
• unset