NAME
    attr - extended attributes on XFS filesystem objects

SYNOPSIS
    attr [ -LRq ] -s attrname [ -V attrvalue ] pathname

    attr [ -LRq ] -g attrname pathname

    attr [ -LRq ] -r attrname pathname

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

    They could be used to store meta-information about the file. For exam-
    ple "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 image.

    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) docu-
    mentation.

    In the XFS filesystem, the names can be up to 256 bytes in length, ter-
    minated 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 mecha-
    nism, so the owner of the file can decide who is  able to see and/or
    modify the value of attributes on any particular file.

DESCRIPTION
    The attr utility allows the manipulation of extended attributes associ-
    ated 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 pro-
    cessing via a piped command.

    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.

    SET/CREATE
    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 itself.

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

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

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

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

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