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    The following form allows you to view linux man pages.

    Command:

    chattr

    
    
    

    SYNOPSIS

           chattr [ -RVf ] [ -v version ] [ mode ] files...
    
    
    

    DESCRIPTION

           chattr changes the file attributes on a Linux file system.
    
           The format of a symbolic mode is +-=[acdeijstuADST].
    
           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  'acdeijstuADST'  select the new attributes for the files:
           append only (a), compressed  (c),  no  dump  (d),  extent  format  (e),
           immutable (i), data journalling (j), secure deletion (s), no tail-merg-
           ing (t), undeletable (u), no atime updates (A),  synchronous  directory
           updates  (D),  synchronous  updates (S), and top of directory hierarchy
           (T).
    
           The following attributes are read-only, and may be listed by  lsattr(1)
           but  not  modified  by  chattr:  huge  file (h), compression error (E),
           indexed directory (I), compression raw access (X), and compressed dirty
           file (Z).
    
    
    

    OPTIONS

           -R     Recursively change attributes of directories and their contents.
    
           -V     Be verbose with chattr's output and print the program version.
    
           -f     Suppress most error messages.
    
           -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 sys-
           tems.
    
           A file with the 'a' attribute set can only be open in append  mode  for
           writing.    Only   the   superuser   or   a   process   possessing  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.
           Note:  please make sure to read the bugs and limitations section at the
           end of this document.
    
           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.
           using chattr(1), although it can be displayed by lsattr(1).
    
           The  'h' attribute indicates the file is storing its blocks in units of
           the filesystem blocksize instead of in units of sectors, and means that
           the file is (or at one time was) larger than 2TB.  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  possessing  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=journal" option all file  data  is
           already  journalled  and  this attribute has no effect.  Only the supe-
           ruser 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.  Note: please make  sure  to  read
           the bugs and limitations section at the end of this document.
    
           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.
           This  is  a  hint to the block allocator used by ext3 and ext4 that the
           subdirectories under this directory are not related, and thus should be
           spread  apart  for allocation purposes.   For example it is a very good
           idea to  set  the  'T'  attribute  on  the  /home  directory,  so  that
           /home/john  and  /home/mary are placed into separate block groups.  For
           directories where this attribute is not set, the Orlov block  allocator
           will try to group subdirectories closer together where possible.
    
           A file with the 't' attribute will not have a partial block fragment at
           the end 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 which don't  understand
           tail-merged files.  Note: As of this writing, the ext2 or ext3 filesys-
           tems do not (yet, except in very experimental  patches)  support  tail-
           merging.
    
           When  a  file  with  the 'u' attribute set is deleted, its contents are
           saved.  This allows the user to ask for its undeletion.   Note:  please
           make  sure  to read the bugs and limitations section at the end of this
           document.
    
           The 'X' attribute is used by the experimental  compression  patches  to
           The 'c', 's',  and 'u' attributes are not honored by the ext2 and  ext3
           filesystems  as  implemented  in  the  current  mainline Linux kernels.
           These attributes may be implemented in future versions of the ext2  and
           ext3 filesystems.
    
           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 1.41.12 May 2010 CHATTR(1)

    
    
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