STRTOFILE("prova","nomefile.extension")
=FILETOSTR("nomefile.extension") && EXISTS
DELETE FILE  "x.ext"
=FILETOSTR("nomefile.extension") && EXISTS
DELETE FILE  "*.ex"
=FILETOSTR("nomefile.extension") && EXISTS
DELETE FILE  "*.exte"
=FILETOSTR("nomefile.extension") && EXISTS
DELETE FILE  "*.ext" && 3 extension chars
=FILETOSTR("nomefile.extension") && DELETED !!!!