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 +-=[ASacdisu].

       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(8) 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

       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.

       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(1)


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