term% ls -F
term% cat index.txt
CHMOD(1)                    General Commands Manual                   CHMOD(1)

       chmod - change mode

       chmod mode file ...

       The  mode of each named file is changed according to mode, which may be
       absolute or symbolic.  An absolute mode is an octal number  constructed
       from the OR of the following modes:

       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 (search in directory) by owner
       0070      read, write, execute (search) by group
       0007      read, write, execute (search) by others

       A symbolic mode has the form:

              [who] op permission [op permission] ...

       The  who  part  is  a  combination of the letters u (for user's permis‐
       sions), g (group) and o (other).  The letter a stands for ugo.  If  who
       is  omitted, the default is a but the setting of the file creation mask
       (see umask(2)) is taken into account.

       Op can be + to add permission to the file's mode, - to take  away  per‐
       mission  and  = to assign permission absolutely (all other bits will be

       Permission is any combination of the letters r  (read),  w  (write),  x
       (execute),  s (set owner or group id) and t (save text - sticky).  Let‐
       ters u, g or o indicate that permission is to be taken from the current
       mode.   Omitting permission is only useful with = to take away all per‐

       The first example denies write permission to others, the second makes a
       file executable:

              chmod o-w file
              chmod +x file

       Multiple  symbolic  modes separated by commas may be given.  Operations
       are performed in the order specified.  The letter s is only useful with
       u or g.

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

       ls(1), chmod(2), chown (1), stat(2), umask(2)