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CHMOD(2)                      System Calls Manual                     CHMOD(2)

       chmod - change mode of file

       chmod(name, mode)
       char *name;

       The  file  whose name is given as the null-terminated string pointed to
       by name has its mode changed to mode.  Modes are constructed  by  ORing
       together some combination of the following:

               04000 set user ID on execution
               02000 set group ID on execution
               01000 save text image after execution
               00400 read by owner
               00200 write by owner
               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 (-n or -i option of ld(1))
       then mode 1000 prevents the system from abandoning the swap-space image
       of  the program-text portion of the file when its last user terminates.
       Thus when the next user of the file executes it, the text need  not  be
       read  from  the  file system but can simply be swapped in, saving time.
       Ability to set this bit is restricted  to  the  super-user  since  swap
       space  is  consumed  by  the images; it is only worth while for heavily
       used commands.

       Only the owner of a file (or the super-user) may change the mode.  Only
       the super-user can set the 1000 mode.


       Zero  is returned if the mode is changed; -1 is returned if name cannot
       be found or if current user is neither the owner of the  file  nor  the

       (chmod = 15.)
       sys chmod; name; mode