-let cols = int_of_string (Sys.getenv "COLUMNS")
+let cols =
+ try int_of_string (Sys.getenv "COLUMNS")
+ with Not_found -> failwith "environment variable COLUMNS not visible"
let hl = ref []
Array.fast_sort compare files;
let c = Array.fold_left (write l) 0 files in
if 0 < c && c < cols then print_newline ();
+