




Command:   chmod - change access mode for files
Syntax:    chmod [-R] mode file ...
Flags:     -R  Change hierarchies recursively
Examples:  chmod 755 file           # Owner: rwx Group: r-x Others: r-x
           chmod +x file1 file2     # Make file1 and file2 executable
           chmod a-w file           # Make file read only
           chmod u+s file           # Turn on SETUID for file
           chmod -R o+w dir         # Allow writing for all files in dir

     The given mode is applied to each file in the file list. If the  -R
flag  is present, the files in a directory will be changed as well.  The
mode can be either absolute or symbolic. Absolute modes are given as  an
octal  number  that  represents  the  new  file  mode. The mode bits are
defined as follows:

   4000    Set effective user id on execution to file's owner id
   2000    Set effective group id on execution to file's group id
   0400    file is readable by the owner of the file
   0200    writeable by owner
   0100    executable by owner
   0070    same as above, for other users in the same group
   0007    same as above, for all other users

Symbolic modes modify the current file mode in a specified way. The form
is:

   [who] op permissions { op permissions ...} {, [who] op ... }

The possibilities for who are u, g, o, and a, standing for user,  group,
other  and  all,  respectively. If who is omitted, a is assumed, but the
current umask is used. The op can be +, -, or =;  + turns on  the  given
permissions,  -  turns  them off; = sets the permissions exclusively for
the given who. For example g=x sets the group permissions to --x.

     The possible permissions are r, w, x; which stand for read,  write,
and  execute;   s  turns on the set effective user/group id bits. s only
makes sense with u and g; o+s is harmless.





















                                                                        

