declare

Additional Notes

declare is a Bash builtin for creating variables and setting attributes such as integer, array, readonly, export, or function display.

Use it in Bash scripts when variable type or scope matters.

Syntax

declare [options] [name[=value] ...]

Parameters

• name: Variable or function name.
• value: Optional value to assign.
• options: Attribute flags.

Common Options

• -i: Treat variable as an integer.
• -a: Declare indexed array.
• -A: Declare associative array.
• -r: Make variable readonly.
• -x: Export variable to child processes.
• -p: Print variable declarations.
• -f: Show function definitions.
• -g: Create global variable inside a function on Bash versions that support it.

Examples

declare -i count=10
count=count+5
echo "$count"

Use integer arithmetic assignment.

declare -A colors
colors[error]=red

Create an associative array.

declare -r app_name="linux-command"

Create a readonly variable.

declare -p PATH

Print a reusable declaration for a variable.

Practical Notes

• declare is Bash-specific; plain sh may not support these features.
• Use local inside functions when you only need function-local variables.
• Arrays and associative arrays require Bash, not POSIX shell.