Data commit

Task/Remove-lines-from-a-file/OCaml/remove-lines-from-a-file.ocaml

@@ -0,0 +1,33 @@
+let input_line_opt ic =
+  try Some (input_line ic)
+  with End_of_file -> None
+
+let delete_lines filename start skip =
+  if start < 1 || skip < 1 then
+    invalid_arg "delete_lines";
+  let tmp_file = filename ^ ".tmp" in
+  let ic = open_in filename
+  and oc = open_out tmp_file in
+  let until = start + skip - 1 in
+  let rec aux i =
+    match input_line_opt ic with
+    | Some line ->
+        if i < start || i > until
+        then (output_string oc line; output_char oc '\n');
+        aux (succ i)
+    | None ->
+        close_in ic;
+        close_out oc;
+        Sys.remove filename;
+        Sys.rename tmp_file filename
+  in
+  aux 1
+
+let usage () =
+  Printf.printf "Usage:\n%s <filename> <startline> <skipnumber>\n" Sys.argv.(0);
+  exit 0
+
+let () =
+  if Array.length Sys.argv < 4 then usage ();
+  delete_lines
+    Sys.argv.(1) (int_of_string Sys.argv.(2)) (int_of_string Sys.argv.(3))