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chmod

Change file mode bits (permissions)

command File ManagementPermissionsSecurity

Overview

Changes the file mode bits of each given file according to mode, which can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new mode bits.

Syntax

chmod [OPTION]... MODE[,MODE]... FILE... 
chmod [OPTION]... OCTAL-MODE FILE... 
chmod [OPTION]... --reference=RFILE FILE...

Common Options

-R, --recursive

Change files and directories recursively.

-v, --verbose

Output a diagnostic for every file processed.

-c, --changes

Like verbose but report only when a change is made.

--reference=RFILE

Use RFILE's mode instead of MODE values.

--silent, --quiet

Suppress most error messages.

Symbolic Modes: u (user), g (group), o (others), a (all)

Classes for symbolic mode.

Symbolic Operators: + (add), - (remove), = (set exactly)

Operators for symbolic mode.

Symbolic Permissions: r (read), w (write), x (execute), X (special execute), s (setuid/gid), t (sticky)

Permissions for symbolic mode.

Examples

$ chmod u+x script.sh

Makes script.sh executable by the user/owner.

$ chmod 755 myfile.txt

Sets read/write/execute for user, and read/execute for group and others (octal).

$ chmod g-w,o-w important_data

Removes write permission for the group and others from important_data.

$ chmod a=r public_file.txt

Sets read-only permission for everyone (user, group, and others).

$ chmod -R u+rw,g+r,o+r project_dir/

Recursively sets read/write for user, and read-only for group and others for all files/directories in project_dir/.

$ chmod --reference=template.sh new_script.sh

Copies permissions from template.sh to new_script.sh.

$ chmod u=rwx,g=rx,o=rx myscript

Sets user to read, write, execute; group to read, execute; others to read, execute.

Related Commands

ls

List directory contents

cp

Copy files and directories

mv

Move or rename files and directories

rm

Remove files or directories

rmdir

Remove empty directories

touch

Change file timestamps or create empty files

permissionsaccessrightsfiledirectorysecuritymodechmod