CHMOD(1)		    UNIX Reference Manual		      CHMOD(1)

NNAAMMEE
     cchhmmoodd change file modes

SSYYNNOOPPSSIISS
     cchhmmoodd [--ffRR] _m_o_d_e _f_i_l_e ...

DDEESSCCRRIIPPTTIIOONN
     The cchhmmoodd utility modifies the file mode bits of the listed files as
     specified by the _m_o_d_e operand.

     The options are as follows:

     --ff    cchhmmoodd will still exit 0 and not complain if it fails to change the
	   mode on a file.

     --RR    Traverse a file hierarchy.  For each file that is of type directo-
	   ry, cchhmmoodd changes the mode of all files in the file hierarchy below
	   it followed by the mode of the directory itself.

     Symbolic links are not indirected through, nor are their modes altered.

     Only the owner of a file or the super-user is permitted to change the
     mode of a file.

     The cchhmmoodd utility exits 0 on success, and >0 if an error occurs.

MMOODDEESS
     Modes may be absolute or symbolic.  An absolute mode is an octal number
     constructed by _o_r'ing the following values:

		 4000	   set-user-ID-on-execution
		 2000	   set-group-ID-on-execution
		 1000	   sticky bit, see chmod(2)
		 0400	   read by owner
		 0200	   write by owner
		 0100	   execute (or search for directories) by owner
		 0070	   read, write, execute/search by group
		 0007	   read, write, execute/search by others


     The read, write, and execute/search values for group and others are en-
     coded as described for owner.

     The symbolic mode is described by the following grammar:

	   mode            ::= clause [, clause]
	   clause	   ::= [who ...] [action ...] last_action
	   action	   ::= op perm ...
	   last_action	   ::= op [perm ...]
	   who		   ::= a | u | g | o
	   op		   ::= + | - | =
	   perm            ::= r | s | t | w |


     The _w_h_o symbols ``u'', ``g'', and ``o'' specify the user, group, and oth-
     er parts of the mode bits, respectively.  The _w_h_o symbol ``a'' is
     equivalent to ``ugo''.

     The _p_e_r_m symbols represent the portions of the mode bits as follows:

	   r	 The read bits.
	   s	 The set-user-ID-on-execution and set-group-ID-on-execution
		 bits.
	   t	 The sticky bit.
	   w	 The write bits.
	   x	 The execute/search bits.
	   X	 The execute/search bits if the file is a directory or any of
		 the execute/search bits are set in the original (unmodified)
		 mode.	Operations with the _p_e_r_m symbol ``X'' are only mean-
		 ingful in conjunction with the _o_p symbol ``+'', and it is ig-
		 nored in all other cases.


     The _o_p symbols represent the operation performed, as follows:

     +	   If no value is supplied for _p_e_r_m, the ``+'' operation has no ef-
	   fect.  If no value is supplied for _w_h_o, each permission bit speci-
	   fied in _p_e_r_m, for which the corresponding bit in the file mode
	   creation mask is clear, is set.  Otherwise, the mode bits
	   represented by the specified _w_h_o and _p_e_r_m values are set.

     -	   If no value is supplied for _p_e_r_m, the ``-'' operation has no ef-
	   fect.  If no value is supplied for _w_h_o, the mode bits represented
	   by _p_e_r_m are cleared for the owner, group and other permissions.
	   Otherwise, the mode bits represented by the specified _w_h_o and _p_e_r_m
	   values are cleared.

     =	   The mode bits specified by the _w_h_o value are cleared, or, if no who
	   value is specified, the owner, group and other mode bits are
	   cleared.  Then, if no value is supplied for _w_h_o, each permission
	   bit specified in _p_e_r_m, for which the corresponding bit in the file
	   mode creation mask is clear, is set.  Otherwise, the mode bits
	   represented by the specified _w_h_o and _p_e_r_m values are set.

     Each _c_l_a_u_s_e specifies one or more operations to be performed on the mode
     bits, and each operation is applied to the mode bits in the order speci-
     fied.

     Operations upon the other permissions only (specified by the symbol ``o''
     by itself), in combination with the _p_e_r_m symbols ``s'' or ``t'', are ig-
     nored.

EEXXAAMMPPLLEESS
     ``644''	 make a file readable by anyone and writable by the owner
		 only.

     ``go-w''	 deny write permission to group and others.

     ``=rw,+X''
		 set the read and write permissions to the usual defaults, but
		 retain any execute permissions that are currently set.

     ``+X''	 make a directory or file searchable/executable by everyone if
		 it is already searchable/executable by anyone.

     ``755'' or ``u=rwx,go=rx''
		 make a file readable/executable by everyone and writeable by
		 the owner only.

     ``go=''	 clear all mode bits for group and others.

BBUUGGSS
     There's no _p_e_r_m option for the naughty bits.

SSEEEE AALLSSOO
     install(1), chmod(2), fts(2), stat(2), umask(2), setmode(3), chown(8)

SSTTAANNDDAARRDDSS
     The cchhmmoodd utility is expected to be POSIX 1003.2 compatible with the ex-
     ception of the _p_e_r_m symbols ``t'' and ``X'' which are not included in
     that standard.