FILECODE...a little utility to change the filecode of files on MPE/iX   
                                                                        
Usage:                                                                  
                                                                        
   :run filecode                                                        
                                                                        
   ...enter the name of the file to change, and optionally the new      
      filecode.                                                         
                                                                        
   ...enter EXIT or // to exit                                          
                                                                        
or                                                                      
                                                                        
   :run filecode; info="filename newfilecode"                           
                                                                        
The "newfilecode" may be a number, or a filecode mnemonic.  Various     
"extra" mnemonics are recognized, including QEDIT (111),                
IROOT (-400), and ISET (-401).                                          
                                                                        
Example:                                                                
                                                                        
   :build foo; code=9                                                   
   :run filecode; info="foo 23"                                         
   :listf foo,3                                                         

20140822