chmod

Refer to http://72.235.176.168/qnxman/chmod.html

chmod

change file modes (POSIX)
Syntax:


chmod [-R] mode file...

Options:

-R
    Recursively change file modes. For each file that names a directory, chmod changes the file mode bits of the directory and all files in the file hierarchy below it.
mode
    Represents the change to be made to the file mode of each file named (see the Description below).
file
    The pathname of a file whose file mode bits are to be modified.

Description:

The chmod utility lets you change any or all of the file permission mode bits of one or more files. For each file you name, chmod changes the file permission mode bits according to the mode operand.

To change a file's permission mode bits, the user of chmod must be either the owner of the file or the superuser.

The mode option can be either a symbolic_mode expression or a non-negative octal integer.
Symbolic Modes

The symbolic_mode has the following form:

    * [[agou] [+-=] [rswx]] [,symbolic_mode]

The options of the symbolic form are:
Global Monitoring Division    
        Home        |        About GMD        |        Research Areas        |        Information and Data        |        Observatories
   
Option    Description
a    user, group, and other access
g    group access
o    other access
u    user access
+    add specified permissions to the group, other, or user category of the specified files
-    remove specified permissions from the group, other, or user category of the specified files
=    set the specified permissions for the group, other, or user category of the specified files
r    read permission
s    set userid or groupid when executed
w    write permission
x    execute permission

The agou specification is optional. When it is not supplied, all the permissions (user, group and other) will be affected, but for + and = operators only those permissions not set in the file creation mask (see umask) will be set.
Some examples of symbolic modes:

Make myfile executable by all:

chmod a+x myfile


Remove read permission for group and others:

chmod og-r myfile


Perform both the above operations, in the order given, on three files: myfile, file2, and zzz:

chmod a+x,og-r myfile file2 zzz