CHATTR(1)						      General Commands Manual							 CHATTR(1)

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 +-=[ASacDdIijsTtu].

       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 `ASacDdijsu' select the new attributes for the files: don't update atime (A), synchronous updates  (S),  synchronous  directory
       updates (D), append only (a), compressed (c), no dump (d), immutable (i), data journalling (j), secure deletion (s), top of directory hier-
       archy (T), no tail-merging (t), 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 program version.

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

ATTRIBUTES

       When  a file with the 'A' attribute set is accessed, 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  or  a  process  pessessing  the
       CAP_LINUX_IMMUTABLE capability can set or clear this attribute.

       A  file with the `c' attribute set is automatically compressed 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.

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

       A file with the `d' attribute set is not candidate for backup when the dump(8) program is run.

       The  'E'  attribute is used by the experimental compression patches to indicate that a compressed file has a compression error.	It may not
       be set or reset using chattr(1), although it can be displayed by lsattr(1).

       The 'I' attribute is used by the htree code to indicate that a directory is behind indexed using hashed trees.  It may not be set or  reset
       using chattr(1), although it can be displayed by lsattr(1).

       A  file	with the `i' attribute cannot be modified: it cannot be deleted or renamed, no link can be created to this file and no data can be
       written to the file.  Only the superuser or a process pessessing the CAP_LINUX_IMMUTABLE capability 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.  Only the superuser or a process possessing  the  CAP_SYS_RESOURCE	capability
       can set or clear this attribute.

       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 directory with the 'T' attribute will be deemed to be the top of directory hierarchies for the purposes  of  the  Orlov  block  allocator
       (which is used in on systems with Linux 2.5.46 or later).

       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.

       The  'X'  attribute  is	used  by the experimental compression patches to indicate that a raw contents of a compressed file can be accessed
       directly.  It currently may not be set or reset using chattr(1), although it can be displayed by lsattr(1).

       The 'Z' attribute is used by the experimental compression patches to indicate a compressed file is dirty.  It may not be set or reset using
       chattr(1), although it can be displayed by lsattr(1).

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.

       The `D' option is only useful on Linux kernel 2.5.19 and later.

AVAILABILITY

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

SEE ALSO

       lsattr(1)

E2fsprogs version 1.32						   November 2002							 CHATTR(1)