setfile
Set attributes of HFS+ files. It attempts to be similar to the 
  setfile command in MPW. It can apply rules to more than one file with the options 
  applying to all files listed.
SYNTAX
      SetFile [-a attributes] [-c creator] [-d date] [-m date] [-t type] file
	     ...
Options
     -a attributes  Sets the file attributes bits where attributes is a string
		    of case sensitive letters. Each letter corresponds to a
		    file attribute: an uppercase letter indicates that the
		    attribute bit is set (1), a lowercase letter indicates
		    that it is not (0).	 Note: attributes not specified remain
		    unchanged.
		    A | a    Alias file
		    B | b    Has bundle
		    C | c    Custom icon (allowed on folders)
		    D | d    Located on the desktop (allowed on folders)
		    E | e    Extension is hidden (allowed on folders)
		    I | i    Inited - Finder is aware of this file and has
			     given it a location in a window. (allowed on
			     folders)
		    L | l    Locked
		    M | m    Shared (can run multiple times)
		    N | n    File has no INIT resource
		    S | s    System file (name locked)
		    T | t    "Stationery Pad" file
		    V | v    Invisible (allowed on folders)
     -c creator	    Specifies the file's creator, where creator is a string of
		    exactly four characters.
     -d date	    Sets the creation date, where date is a string of the
		    form: "mm/dd/[yy]yy [hh:mm:[:ss] [AM | PM]]" Notes:
		    Enclose the string in quotation marks if it contains
		    spaces. Period '.' represents the current date and time.
		    [yy]yy < 100 assumes 21th century, e.g.20yy.
     -m date	    Sets the modification date where date is a string of the
		    form in -d above. (mm/dd/[yy]yy [hh:mm:[:ss] [AM | PM]])
     -t type	    Sets the file type, where type is a string of exactly four
		    characters.
SetFile is part of
/Developer/Tools/
EXAMPLES
     Set the creator and type for the ResEqual tool:
       SetFile -c "MPS " -t MPST ResEqual
     Set the modification date of "myFile":
        SetFile -m "8/4/2001 16:13" myFile
Return Values
  0 - attributes set
  1 - syntax error 
  2 - any other error 
"The more the merrier" - John Heywood
Related commands:
  
  chflags - Change a file or folder's flags.
  GetFileInfo - Get attributes of HFS+ files
textutil - Manipulate text files in various formats