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CHMOD(1)			      FSF			      CHMOD(1)

NAME
       chmod - change file access permissions

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

DESCRIPTION
       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
       existing	 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), save
       program text on swap device (t), the permissions that the user who owns
       the  file currently has for it (u), the permissions that other users in
       the file's group have for it (g), and the permissions that other	 users
       not in the file's group have for it (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 save text image (1) attributes.  The  sec‐
       ond 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 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.

OPTIONS
       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

       --reference=RFILE
	      use RFILE's mode instead of MODE values

       -R, --recursive
	      change files and directories recursively

       --help display this help and exit

       --version
	      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.

AUTHOR
       Written by David MacKenzie.

REPORTING BUGS
       Report bugs to <bug-fileutils@gnu.org>.

COPYRIGHT
       Copyright © 2001 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
       PURPOSE.

SEE ALSO
       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 (fileutils) 4.1		  April 2001			      CHMOD(1)

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