Linux in a Nutshell, 6th Edition

Name

chattr

Synopsis

chattr [options] mode files

Modify file attributes. Specific to Linux Second and Third Extended Filesystems (ext2 and ext3). Like symbolic chmod, chattr specifies attributes with +, -, and = but it operates on extended file attributes (see the upcoming section Attributes). mode is in the form opcode attribute. See also lsattr.

Options

-R

Modify directories and their contents recursively.

-f

Suppress most error messages.

-V

Verbose; print modes of attributes after changing them.

-v version

Set the file’s version.

Opcodes

+

Add attribute.

-

Remove attribute.

=

Assign attributes (removing unspecified attributes).

Attributes

A

Don’t update access time on modify.

a

Append only for writing. Can be set or cleared only by a privileged user.

c

Compressed.

D

Write changes synchronously to disk.

d

No dump.

H

The file’s blocks are stored in units of the filesystem blocksize, not of sectors. The file is or was at one time larger than 2 TB.

I

A directory is indexed using hashed trees.

i

Immutable. Can be set or cleared only by a privileged user. A file marked as immutable cannot be deleted, renamed, modified, or linked to until the setting has been cleared.

j

Journalled file. This is useful only in cases where you are using an ext3 filesystem mounted with the data="ordered” or data="writeback” attributes. The data="journal” option for the filesystem causes this operation to be performed for all files in the system and makes this option irrelevant.

S

Synchronous updates.

s

Secure deletion. The contents are zeroed ...