$ ./perl/tst.pl 
] m
m
] n
n
] o
o
] B tst.bat
B tst.bat
INFO: Opening batch file tst.bat
] a
] b
] c
] d
] e
] B tst2.bat
INFO: Opening batch file tst2.bat
] 1
] 2
] 3
] z
] y
] x
] w
] INFO: Current IO: tst.bat
] INFO: Current IO: STDIN
] No other input. Ending. at ./perl/tst.pl line 41, <STDIN> line 17.