MPL Bytecode Compiler Code

21 lines (18 with data), 450 Bytes

##LIBHDR

.(;I,F,S%.STR.) [
  .ARGC.()<>2 ? WRITEF("USAGE: %S <FILENAME>*N", .ARGV.(S$,1)) : [
    (F=SELECTINPUT(FINDINPUT(.ARGV.(S$,2)))) ? [
      I=0; READS(S$) @ [
        WRITEF("%I3: %S*N", ++I, S$);
        ==(I\20)?[
          F=SELECTINPUT(F);
          WRITES("PRESS ENTER:"); READS(S$);
          F=SELECTINPUT(F)
        ]
      ];
      ENDREAD();
      SELECTINPUT(F)
    ] : WRITES("FILE NOT FOUND*N")
  ];
  0
]