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CHMOD(1)			      FSF			      CHMOD(1)

       chmod - change file access permissions

       chmod [OPTION]... MODE[,MODE]...	FILE...
       chmod [OPTION]... OCTAL-MODE FILE...
       chmod [OPTION]... --reference=RFILE FILE...

       This manual page	documents the GNU version of chmod.  chmod changes the
       permissions of each given file according	to mode, which can be either a
       symbolic	 representation	 of changes to make, or	an octal number	repre-
       senting the bit pattern for the new permissions.

       The   format   of   a   symbolic	  mode	 is    `[ugoa...][[+-=][rwxXs-
       tugo...]...][,...]'.   Multiple symbolic	operations can be given, sepa-
       rated by	commas.

       A combination of	the letters `ugoa' controls which users' access	to the
       file  will  be  changed:	 the  user who owns it (u), other users	in the
       file's group (g), other users not in the	file's group (o), or all users
       (a).   If  none of these	are given, the effect is as if `a' were	given,
       but bits	that are set in	the umask are not affected.

       The operator `+'	causes the permissions selected	to be added to the ex-
       isting permissions of each file;	`-' causes them	to be removed; and `='
       causes them to be the only permissions that the file has.

       The letters `rwxXstugo' select the new  permissions  for	 the  affected
       users:  read  (r),  write (w), execute (or access for directories) (x),
       execute only if the file	is a directory or already has execute  permis-
       sion  for  some user (X), set user or group ID on execution (s),	sticky
       (t), the	permissions granted to the user	who owns  the  file  (u),  the
       permissions  granted to other users who are members of the file's group
       (g), and	the permissions	granted	to users that are in  neither  of  the
       two preceding categories	(o).

       A  numeric  mode	 is  from  one	to four	octal digits (0-7), derived by
       adding up the bits with values 4, 2, and	1.  Any	omitted	digits are as-
       sumed to	be leading zeros.  The first digit selects the set user	ID (4)
       and set group ID	(2) and	sticky (1) attributes.	The second  digit  se-
       lects  permissions for the user who owns	the file: read (4), write (2),
       and execute (1);	the third selects permissions for other	users  in  the
       file's  group, with the same values; and	the fourth for other users not
       in the file's group, with the same values.

       chmod never changes the permissions of symbolic links; the chmod	system
       call  cannot change their permissions.  This is not a problem since the
       permissions of symbolic links are never used.  However, for  each  sym-
       bolic link listed on the	command	line, chmod changes the	permissions of
       the pointed-to file.  In	contrast, chmod	ignores	symbolic links encoun-
       tered during recursive directory	traversals.

       On  older  Unix	systems,  the sticky bit caused	executable files to be
       hoarded in swap space.  This feature is not useful on  modern  VM  sys-
       tems, and the Linux kernel ignores the sticky bit on files.  Other ker-
       nels may	use the	sticky bit on files for	system-defined	purposes.   On
       some systems, only the superuser	can set	the sticky bit on files.

       When  the sticky	bit is set on a	directory, files in that directory may
       be unlinked or renamed only by root or their owner.  Without the	sticky
       bit,  anyone able to write to the directory can delete or rename	files.
       The sticky bit is commonly found	on directories,	such as	/tmp, that are

       Change the mode of each FILE to MODE.

       -c, --changes
	      like verbose but report only when	a change is made

       -f, --silent, --quiet
	      suppress most error messages

       -v, --verbose
	      output a diagnostic for every file processed

	      use RFILE's mode instead of MODE values

       -R, --recursive
	      change files and directories recursively

       --help display this help	and exit

	      output version information and exit

       Each  MODE  is  one or more of the letters ugoa,	one of the symbols +-=
       and one or more of the letters rwxXstugo.

       Written by David	MacKenzie.

       Report bugs to <>.

       Copyright (C) 2002 Free Software	Foundation, Inc.
       This is free software; see the source for copying conditions.  There is
       NO  warranty;  not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR

       The full	documentation for chmod	is maintained as a Texinfo manual.  If
       the  info  and  chmod programs are properly installed at	your site, the

	      info chmod

       should give you access to the complete manual.

chmod (coreutils) 4.5.3		 February 2003			      CHMOD(1)


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