Permissions

Linux chmod command

Change file permissions. This example grants the owner execute permission.

Availability: Common Linux commands; shell built-ins and external implementations may differ by distribution.中文

Syntax

chmod [OPTION]... MODE FILE...

Examples

Add execute permission for the owner.

chmod u+x ./script.sh

Set owner read/write and group read permissions.

chmod 640 ./secrets.txt

Parameters, options and clauses

Option / clause	Description
`MODE (symbolic)`	Use forms such as u+x, go-w or a=rx.
`MODE (numeric)`	Use octal digits such as 640 or 755.
`-R, --recursive`	Change permissions recursively (directories and contents).
`-v, --verbose`	Report every processed file.
`-c, --changes`	Report only files whose permissions changed.
`-f, --silent`	Suppress most error messages.
`--reference=FILE`	Use FILE's mode instead of MODE.

Safety note

Review a command and its target before running it. Commands that alter files, services, accounts, disks, permissions or databases may be difficult to reverse. Test in a safe environment and keep backups.

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