$ time ./file_map.pl patternabc big_file
File 'big_file' doesn't match

real  0m0.327s
user  0m0.267s
sys   0m0.060s

$ time ./mce_slurp.pl patternabc big_file
File 'big_file' doesn't match

real  0m0.152s
user  0m0.263s
sys   0m0.118s