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declare - Unix, Linux Command
NAME
declare - Declare variables and give them attributes.
SYNOPSIS
declare [-afFrxi] [-p] [name[=value]]
DESCRIPTION
If no names are given, then 'declare' will display the values of variables instead. Using + instead of - turns off the attribute instead. When used in a function, declare makes each name local, as with the local command. The typeset command is supplied for compatibility with the Korn shell; however, it has been deprecated in favor of the declare builtin command. The return status is zero unless an invalid option is encountered, an attempt is made to define a function using '-f foo=bar', an attempt is made to assign a value to a readonly variable, an attempt is made to assign a value to an array variable without using the compound assignment syntax, one of the names is not a valid shell variable name, an attempt is made to turn off readonly status for a readonly variable, an attempt is made to turn off array status for an array variable, or an attempt is made to display a non-existent function with '-f'.
OPTIONS
Tag | Description |
---|---|
-a | Each name is an array variable. |
-f | Use function names only. |
-F | Inhibit the display of function definitions; only the function name and attributes are printed. (implies -f) |
-i | The variable is to be treated as an integer; arithmetic evaluation is performed when the variable is assigned a value. |
-p | Display the attributes and values of each name. When '-p' is used, additional options are ignored. |
-r | Make names readonly. These names cannot then be assigned values by subsequent assignment statements or unset. |
-x | Mark each name for export to subsequent commands via the environment. |
EXAMPLES
$ declare | grep HOME HOME=/home/bozo
$ zzy=68 $ declare | grep zzy zzy=68
$ Colors=([0]="purple" [1]="reddish-orange" [2]="light green") $ echo ${Colors[@]} purple reddish-orange light green
bash$ declare | grep Colors Colors=([0]="purple" [1]="reddish-orange" [2]="light green")Print