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RedHat 9 (Linux i386) - man page for attr (redhat section 1)

ATTR(1) 			      XFS Compatibility API				  ATTR(1)

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  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 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 set-
       fattr(1) documentation.

       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,  sym-
       bolic 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.

DESCRIPTION
       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.

       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  output  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) program will.

CAVEATS
       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.

SEE ALSO
       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)


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