Linux Commands: Declare variables and give them attributes
declare-Linux Command
declare command- Declare variables and give them attributes
Syntax: declare [-afFrxi] [-p] [name[=value]]
Description: The declare command can be helpful in identifying variables, environmental or otherwise. This can be especially useful with arrays.
-r readonly
(declare -r var1 works the same as readonly var1)
This is the rough equivalent of the C const type qualifier. An attempt to change the value of a readonly variable fails with an error message.
-i integer
Certain arithmetic operations are permitted for declared integer variables without the need for expr or let.
-a array
The variable indices will be treated as an array.
-f function(s)
A declare -f line with no arguments in a script causes a listing of all the functions previously defined in that script.
A declare -f function_name in a script lists just the function named.
-x export
This declares a variable as available for exporting outside the environment of the script itself.
-x var=$value
The declare command permits assigning a value to a variable in the same statement as setting its properties.
Example:
Related:
Other Linux Commands:
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