Variables
Preface a variable by a dollar sign ($
) to reference its value. You can also optionally enclose it in braces ({ }
). You can assign a value to a variable through an equals sign (=
) with no whitespace on either side of it:
$ TMP=temp.file
By default, variables are seen only within the shell itself; to pass variables to other programs invoked within the shell, see the export built-in command.
If followed by an index enclosed by brackets ([ ]
), the variable is considered an array variable. For instance:
$ DIR_LIST[0]=src $ DIR_LIST[1]=headers $ ls ${DIR_LIST[1]}
The contents of headers are listed. Many substitutions and commands in this chapter handle arrays by operating on each element separately.
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