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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 representing the bit pattern for the new permissions.

       The format of a symbolic mode is `[ugoa...][[+-=][rwxXstugo...]...][,...]'.  Multiple sym-
       bolic operations can be given, separated 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 existing permissions
       of each file; `-' causes them to be removed; and `=' causes them to be  the  only  permis-
       sions 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 permission 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 assumed 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 selects 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 val-
       ues; 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 symbolic link listed on the command line, chmod changes the
       permissions of the pointed-to file.  In contrast, chmod ignores symbolic links encountered
       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 systems, and the Linux kernel ignores  the  sticky
       bit  on files.  Other kernels 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 world-writable.

       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 <bug-coreutils@gnu.org>.

       Copyright (C) 2002 Free Software Foundation, Inc.
       This is free software; see the source for copying conditions.  There is NO  warranty;  not

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

	      info chmod

       should give you access to the complete manual.

chmod (coreutils) 4.5.3 		  February 2003 				 CHMOD(1)
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