ATTR(1)                       XFS Compatibility API                      ATTR(1)

       attr - extended attributes on XFS filesystem objects

       attr [ -LRSq ] -s attrname [ -V attrvalue ] pathname

       attr [ -LRSq ] -g attrname pathname

       attr [ -LRSq ] -r attrname pathname

       attr [ -LRSq ] -l pathname

       Extended attributes implement the ability for a user to attach name:value
       pairs to objects within the XFS filesystem.

       This document describes the attr command, which is mostly compatible with
       the IRIX command of the same name.  It is thus aimed specifically at
       users of the XFS filesystem - for filesystem independent extended
       attribute manipulation, consult the getfattr(1) and setfattr(1)

       Extended attributes can be used to store meta-information about the file.
       For example "character-set=kanji" could tell a document browser to use
       the Kanji character set when displaying that document and "thumbnail=..."
       could provide a reduced resolution overview of a high resolution graphic

       In the XFS filesystem, the names can be up to 256 bytes in length,
       terminated by the first 0 byte.  The intent is that they be printable
       ASCII (or other character set) names for the attribute.  The values can
       be up to 64KB of arbitrary binary data.

       Attributes can be attached to all types of XFS inodes: regular files,
       directories, symbolic links, device nodes, etc.

       XFS uses 2 disjoint attribute name spaces associated with every
       filesystem object.  They are the root and user address spaces.  The root
       address space is accessable only to the superuser, and then only by
       specifying a flag argument to the function call.  Other users will not
       see or be able to modify attributes in the root address space.  The user
       address space is protected by the normal file permissions mechanism, so
       the owner of the file can decide who is able to see and/or modify the
       value of attributes on any particular file.

       The attr utility allows the manipulation of extended attributes
       associated with filesystem objects from within shell scripts.

       There are four main operations that attr can perform:

       GET    The -g attrname option tells attr to search the named object and
              print (to stdout) the value associated with that attribute name.
              With the -q flag, stdout will be exactly and only the value of the
              attribute, suitable for storage directly into a file or processing
              via a piped command.

       LIST   The -l option tells attr to list the names of all the attributes
              that are associated with the object, and the number of bytes in
              the value of each of those attributes.  With the -q flag, stdout
              will be a simple list of only the attribute names, one per line,
              suitable for input into a script.

       REMOVE The -r attrname option tells attr to remove an attribute with the
              given name from the object if the attribute exists.  There is no
              output on sucessful completion.

              The -s attrname option tells attr to set the named attribute of
              the object to the value read from stdin.  If an attribute with
              that name already exists, its value will be replaced with this
              one.  If an attribute with that name does not already exist, one
              will be created with this value.  With the -V attrvalue flag, the
              attribute will be set to have a value of attrvalue and stdin will
              not be read.  With the -q flag, stdout will not be used.  Without
              the -q flag, a message showing the attribute name and the entire
              value will be printed.

       When the -L option is given and the named object is a symbolic link,
       operate on the attributes of the object referenced by the symbolic link.
       Without this option, operate on the attributes of the symbolic link

       When the -R option is given and the process has appropriate privileges,
       operate in the root attribute namespace rather that the USER attribute

       The -S option is similar, except it specifies use of the security
       attribute namespace.

       When the -q option is given attr will try to keep quiet.  It will output
       error messages (to stderr) but will not print status messages (to

       The standard file interchange/archive programs tar(1), and cpio(1) will
       not archive or restore extended attributes, while the xfsdump(8) program

       The list option present in the IRIX version of this command is not
       supported.  getfattr provides a mechanism to retrieve all of the
       attribute names.

       getfattr(1), setfattr(1), attr_get(3), attr_set(3), attr_multi(3),
       attr_remove(3), attr(5), and xfsdump(8).

Dec 2001                       Extended Attributes                       ATTR(1)