Variables Summary
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$1, $2, ...
	The first, second, etc command-line arguments to the script.
variable=value
	To set a value for a variable. Remember, no spaces on either side of =
Quotes " '
	Double will do variable substitution, single will not.
variable=$( command )
	Save the output of a command into a variable
export var1
	Make the variable var1 available to child processes.

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Important Concepts!
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Formatting
	The presence or absence of spaces is important.
Manageability
	If a particular value is used several times within a script (eg a file or directory name) then using a variable can make it easier to manage.