$ ls -lh
total 1705800
-rw-r--r--  1 mario  staff    96M Dec  1 01:17 input_a.kct
-rw-r--r--  1 mario  staff   281B Dec  1 01:15 input_a.pl
-rw-r--r--  1 mario  staff   124M Dec  1 01:15 input_a.txt
-rw-r--r--  1 mario  staff   349B Dec  1 01:15 input_b.pl
-rw-r--r--  1 mario  staff   207M Dec  1 01:16 input_b.txt
-rw-r--r--  1 mario  staff   381M Dec  1 01:18 output.txt
-rw-r--r--  1 mario  staff   797B Dec  1 01:12 stage_a.pl
-rw-r--r--  1 mario  staff   824B Dec  1 01:10 stage_b.pl

$ wc -l *.txt
  9999990 input_a.txt
 16666650 input_b.txt
 26666640 output.txt
 53333280 total