Linux: sudo echo 1 >/proc/sys/vm/drop_caches
macOS: sudo purge

$ time wc lesms10_big.txt 
 14152200 113528600 652751200 lesms10_big.txt

real 0m2.435s
user 0m2.330s
sys  0m0.098s

Linux: sudo echo 1 >/proc/sys/vm/drop_caches
macOS: sudo purge

$ time ./wc.pl lesms10_big.txt  
 14152200 113528600 652751200 lesms10_big.txt

real 0m0.662s  (3.68x)
user 0m3.598s
sys  0m0.736s