$ diff -u llil5.ijs llil5p.ijs 
--- llil5.ijs	2023-01-18 09:25:14.041515970 -0600
+++ llil5p.ijs	2023-01-18 09:25:58.889669110 -0600
@@ -9,6 +9,12 @@
 
 pattern =: 0 1
 
+nthrs =: 2!:5 'NUM_THREADS'           NB. get_env NUM_THREADS
+{{
+  if. nthrs do. nthrs =: ".nthrs end. NB. string to integer conversion
+  for. i. nthrs do. 0 T. 0 end.       NB. spin nthrs
+}} ''
+
 args   =: 2 }. ARGV
 fn_out =: {: args
 fn_in  =: }: args
@@ -44,7 +50,7 @@
 read_many_files =: {{
   'fnames pattern' =. y
 
-  ,&.>/"2 (-#pattern) ]\ ,(read_file @:(; &pattern)) "0 fnames
+  ,&.>/"2 (-#pattern) ]\ ,;(read_file @:(; &pattern)) t.'' "0 fnames
 }}
 
 'words nums' =: read_many_files fn_in ; pattern