CHATTR(R)                                               CHATTR(R)



NAME
       chattr - change file attributes on a Linux second extended
       file system

SYNOPSIS
       chattr [ -RV ] [ -v version ] [ mode ] files...

DESCRIPTION
       chattr changes the  file  attributes  on  a  Linux  second
       extended file system.

       The format of a symbolic mode is +-=[ASacdistu].

       The  operator  `+'  causes  the  selected attributes to be
       added to the existing attributes of the files; `-'  causes
       them  to  be  removed;  and `=' causes them to be the only
       attributes that the files have.

       The letters `ASacdijsu' select the new attributes for  the
       files:  don't  update  atime (A), synchronous updates (S),
       append only (a), compressed (c), no  dump  (d),  immutable
       (i),  data  journalling  (j),  secure  deletion  (s),  and
       undeletable (u).

OPTIONS
       -R     Recursively change attributes  of  directories  and
              their  contents.  Symbolic links encountered during
              recursive directory traversals are ignored.

       -V     Be verbose with chattr's output and print the  pro-
              gram version.

       -v version
              Set the file's version/generation number.

ATTRIBUTES
       When  a  file  with the 'A' attribute set is modified, its
       atime record is  not  modified.   This  avoids  a  certain
       amount of disk I/O for laptop systems.

       A  file  with  the  `a'  attribute set can only be open in
       append mode for writing.  Only the superuser  can  set  or
       clear this attribute.

       A  file  with  the `c' attribute set is automatically com-
       pressed on the disk by the kernel. A read from  this  file
       returns uncompressed data. A write to this file compresses
       data before storing them on the disk.

       A file with the `d' attribute set  is  not  candidate  for
       backup when the dump(p) program is run.

       A  file with the `i' attribute cannot be modified: it can-
       not be deleted or renamed, no link can be created to  this
       file  and  no  data  can  be written to the file. Only the
       superuser can set or clear this attribute.

       A file with the `j' attribute has all of its data  written
       to  the  ext3  journal  before  being  written to the file
       itself,  if   the   filesystem   is   mounted   with   the
       "data=ordered"  or  "data=writeback"  options.   When  the
       filesystem is mounted with  the  "data=journalled"  option
       all file data is already journalled and this attribute has
       no effect.

       When a file with the `s' attribute  set  is  deleted,  its
       blocks are zeroed and written back to the disk.

       When  a  file  with the `S' attribute set is modified, the
       changes are written synchronously on  the  disk;  this  is
       equivalent  to the `sync' mount option applied to a subset
       of the files.

       A file with the 't' attribute  will  not  have  a  partial
       block  fragment at the of the file merged with other files
       (for those filesystems which support tail-merging).   This
       is  necessary for applications such as LILO which read the
       filesystem directly, and who don't understand  tail-merged
       files.

       When  a  file  with  the `u' attribute set is deleted, its
       contents are saved.  This allows the user to ask  for  its
       undeletion.


AUTHOR
       chattr was written by Remy Card <Remy.Card@linux.org>.

BUGS AND LIMITATIONS
       As  of Linux 2.2, the `c', 's',  and `u' attribute are not
       honored by the kernel filesystem code.    These attributes
       will be implemented in a future ext2 fs version.

       The `j' option is only useful if the filesystem is mounted
       as ext3.

AVAILABILITY
       chattr is part of the e2fsprogs package and  is  available
       from http://e2fsprogs.sourceforge.net.

SEE ALSO
       lsattr(r)



E2fsprogs version 1.27      March 2002                  CHATTR(R)