Linux in a Nutshell, Fifth Edition

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Chapter 3: Linux Commands

This is the Title of the Book, eMatter Edition

Copyright © 2006 O’Reilly & Associates, Inc. All rights reserved.

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 privi-

leged user.

c Compressed.

d No dump.

i Immutable. Can be set or cleared only by a privileged user.

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="journalled" 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 on deletion, and the

file cannot be undeleted or recovered in any way.

u Undeletable. This causes a file to be saved even after it has

been deleted, so that a user can undelete it later.

Example

chattr +a myfile As superuser

chfn

chfn [options] [username]

Change the information that is stored in /etc/passwd and displayed

to the finger query. Without options, chfn enters interactive mode

and prompts for changes. To make a field blank, enter the keyword

none. Only a privileged user can change information for another

user. For regular users, chfn prompts for the user’s password

before making the change.

Options ...