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BSD 2.11 - man page for chmod (bsd section 2)

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CHMOD(2)										 CHMOD(2)

NAME
       chmod - change mode of file

SYNOPSIS
       chmod(path, mode)
       char *path;
       int mode;

       fchmod(fd, mode)
       int fd, mode;

DESCRIPTION
       The  file  whose  name  is  given  by path or referenced by the descriptor fd has its mode
       changed to mode.  Modes are constructed by or'ing together some combination of the follow-
       ing, defined in <sys/inode.h>:

	      ISUID   04000   set user ID on execution
	      ISGID   02000   set group ID on execution
	      ISVTX   01000   `sticky bit' (see below)
	      IREAD   00400   read by owner
	      IWRITE  00200   write by owner
	      IEXEC   00100   execute (search on directory) by owner
		      00070   read, write, execute (search) by group
		      00007   read, write, execute (search) by others

       If  an  executable  file  is set up for sharing (this is the default) then mode ISVTX (the
       `sticky bit') prevents the system from abandoning the swap-space image of the program-text
       portion	of the file when its last user terminates.  Ability to set this bit on executable
       files is restricted to the super-user.

       If mode ISVTX (the `sticky bit') is set on a  directory,  an  unprivileged  user  may  not
       delete  or rename files of other users in that directory.  For more details of the proper-
       ties of the sticky bit, see sticky(8).

       Only the owner of a file (or the super-user) may change the mode.

       Writing or changing the owner of a file turns off the set-user-id  and  set-group-id  bits
       unless the user is the super-user.  This makes the system somewhat more secure by protect-
       ing set-user-id (set-group-id) files from remaining set-user-id (set-group-id) if they are
       modified, at the expense of a degree of compatibility.

RETURN VALUE
       Upon  successful  completion,  a  value	of  0  is  returned.  Otherwise, a value of -1 is
       returned and errno is set to indicate the error.

ERRORS
       Chmod will fail and the file mode will be unchanged if:

       [ENOTDIR]      A component of the path prefix is not a directory.

       [EINVAL]       The pathname contains a character with the high-order bit set.

       [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire  path  name
		      exceeded 1023 characters.

       [ENOENT]       The named file does not exist.

       [EACCES]       Search permission is denied for a component of the path prefix.

       [ELOOP]	      Too many symbolic links were encountered in translating the pathname.

       [EPERM]	      The  effective  user ID does not match the owner of the file and the effec-
		      tive user ID is not the super-user.

       [EROFS]	      The named file resides on a read-only file system.

       [EFAULT]       Path points outside the process's allocated address space.

       [EIO]	      An I/O error occurred while reading from or writing to the file system.

       Fchmod will fail if:

       [EBADF]	      The descriptor is not valid.

       [EINVAL]       Fd refers to a socket, not to a file.

       [EROFS]	      The file resides on a read-only file system.

       [EIO]	      An I/O error occurred while reading from or writing to the file system.

SEE ALSO
       chmod(1), open(2), chown(2), stat(2), sticky(8)

4th Berkeley Distribution		   May 13, 1986 				 CHMOD(2)
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