Info Catalog coreutils: Conditional Executability coreutils: Symbolic Modes coreutils: Umask and Protection

coreutils: Multiple Changes

 
 27.2.5 Making Multiple Changes
 ------------------------------
 
 The format of symbolic modes is actually more complex than described
 above (⇒Setting Permissions).  It provides two ways to make
 multiple changes to files’ mode bits.
 
    The first way is to specify multiple OPERATION and PERMISSIONS parts
 after a USERS part in the symbolic mode.
 
    For example, the mode:
 
      og+rX-w
 
 gives users other than the owner of the file read permission and, if it
 is a directory or if someone already had execute permission to it, gives
 them execute/search permission; and it also denies them write permission
 to the file.  It does not affect the permission that the owner of the
 file has for it.  The above mode is equivalent to the two modes:
 
      og+rX
      og-w
 
    The second way to make multiple changes is to specify more than one
 simple symbolic mode, separated by commas.  For example, the mode:
 
      a+r,go-w
 
 gives everyone permission to read the file and removes write permission
 on it for all users except its owner.  Another example:
 
      u=rwx,g=rx,o=
 
 sets all of the permission bits for the file explicitly.  (It gives
 users who are not in the file’s group no permission at all for it.)
 
    The two methods can be combined.  The mode:
 
      a+r,g+x-w
 
 gives all users permission to read the file, and gives users who are in
 the file’s group permission to execute/search it as well, but not
 permission to write to it.  The above mode could be written in several
 different ways; another is:
 
      u+r,g+rx,o+r,g-w
 

Info Catalog coreutils: Conditional Executability coreutils: Symbolic Modes coreutils: Umask and Protection