searchreplacefiles_shell

  SEARCHREPLACEFILES_SHELL - search and replace text in all files in a directory search

   SEARCHREPLACEFILES_SHELL(DIRSEARCH, FINDSTRING, REPLACESTRING)

   Searches all of the files in the string DIRSEARCH (examples: '*.m', 
   or '*/*.m') for occurrances of the string FINDSTRING and replaces those
   strings with REPLACESTRING.

   At present, this requires unix (it calls the shell commands 'find' and 'sed').

   The function prints its shell command before attempting to run.