diff --git a/.depend b/.depend
index 188da25a..374fe4ff 100644
--- a/.depend
+++ b/.depend
@@ -676,13 +676,11 @@ src/rule.cmi : \
     src/my_std.cmi \
     src/command.cmi
 src/shell.cmo : \
-    src/tags.cmi \
     src/my_unix.cmi \
     src/my_std.cmi \
     src/log.cmi \
     src/shell.cmi
 src/shell.cmx : \
-    src/tags.cmx \
     src/my_unix.cmx \
     src/my_std.cmx \
     src/log.cmx \
diff --git a/src/command.ml b/src/command.ml
index 35a4b8eb..44497cc7 100644
--- a/src/command.ml
+++ b/src/command.ml
@@ -280,33 +280,7 @@ let execute_many ?(quiet=false) ?(pretend=false) cmds =
       else
         begin
           reset_filesys_cache ();
-          if Sys.win32 then
-            let res, opt_exn =
-              List.fold_left begin fun (acc_res, acc_exn) cmds ->
-                match acc_exn with
-                | None ->
-                    begin try
-                      List.iter begin fun action ->
-                        let cmd = action () in
-                        (* Redirect stderr to stdout to match the
-                           behavior of My_unix.execute_many *)
-                        let rc = sys_command (cmd ^ " 2>&1") in
-                        if rc <> 0 then begin
-                          if not quiet then
-                            eprintf "Command exited with code %d." rc;
-                          raise (Exit_with_code rc)
-                        end
-                      end cmds;
-                      true :: acc_res, None
-                    with e -> false :: acc_res, Some e
-                    end
-                | Some _ -> false :: acc_res, acc_exn
-              end ([], None) konts
-            in match opt_exn with
-            | Some(exn) -> Some(List.rev res, exn)
-            | None -> None
-          else
-            My_unix.execute_many ~ticker ?max_jobs ~display konts
+          My_unix.execute_many ~ticker ?max_jobs ~display konts
         end
     end
 ;;
diff --git a/src/ocamlbuild_executor.ml b/src/ocamlbuild_executor.ml
index 8e5b0977..b9aeb74b 100644
--- a/src/ocamlbuild_executor.ml
+++ b/src/ocamlbuild_executor.ml
@@ -73,7 +73,10 @@ let output_lines prefix oc buffer =
         try String.index_from u i '\n'
         with Not_found -> m
       in
-      output_line i j;
+      (* ignore trailing CR *)
+      let k = ref j in
+      while !k > (i : int) && u.[!k - 1] = '\r' do decr k done;
+      output_line i !k;
       loop (j + 1)
     else
       ()
@@ -133,11 +136,18 @@ let execute
   (* ***)
   (*** add_job *)
   let add_job cmd rest result id =
+    let cmd =
+      if Sys.win32
+      then "bash --norc -c " ^ Filename.quote cmd
+      else cmd
+    in
     (*display begin fun oc -> fp oc "Job %a is %s\n%!" print_job_id id cmd; end;*)
     let (stdout', stdin', stderr') = open_process_full cmd env in
     incr jobs_active;
-    set_nonblock (doi stdout');
-    set_nonblock (doi stderr');
+    if not Sys.win32 then begin
+      set_nonblock (doi stdout');
+      set_nonblock (doi stderr');
+    end;
     let job =
       { job_id          = id;
         job_command     = cmd;
@@ -245,8 +255,10 @@ let execute
       decr jobs_active;
 
       (* PR#5371: we would get EAGAIN below otherwise *)
-      clear_nonblock (doi job.job_stdout);
-      clear_nonblock (doi job.job_stderr);
+      if not Sys.win32 then begin
+        clear_nonblock (doi job.job_stdout);
+        clear_nonblock (doi job.job_stderr);
+      end;
 
       do_read ~loop:true (doi job.job_stdout) job;
       do_read ~loop:true (doi job.job_stderr) job;
diff --git a/src/shell.ml b/src/shell.ml
index 5bcc6b6b..8bbd853b 100644
--- a/src/shell.ml
+++ b/src/shell.ml
@@ -24,33 +24,36 @@ let is_simple_filename s =
     | 'a'..'z' | 'A'..'Z' | '0'..'9' | '.' | '-' | '/' | '_' | ':' | '@' | '+' | ',' -> loop (pos + 1)
     | _ -> false in
   loop 0
+
+(*** Copied from ocaml/stdlib/filename.ml *)
+let generic_quote quotequote s =
+  let l = String.length s in
+  let b = Buffer.create (l + 20) in
+  Buffer.add_char b '\'';
+  for i = 0 to l - 1 do
+    if s.[i] = '\''
+    then Buffer.add_string b quotequote
+    else Buffer.add_char b s.[i]
+  done;
+  Buffer.add_char b '\'';
+  Buffer.contents b
+
+let unix_quote = generic_quote "'\\''"
+
 let quote_filename_if_needed s =
   if is_simple_filename s then s
-  (* We should probably be using [Filename.unix_quote] except that function
-   * isn't exported. Users on Windows will have to live with not being able to
-   * install OCaml into c:\o'caml. Too bad. *)
-  else if Sys.win32 then Printf.sprintf "'%s'" s
-  else Filename.quote s
+  else unix_quote s
+
 let chdir dir =
   reset_filesys_cache ();
   Sys.chdir dir
-let run args target =
+let run args =
   reset_readdir_cache ();
   let cmd = String.concat " " (List.map quote_filename_if_needed args) in
-  if Sys.win32 then
-    begin
-      Log.event cmd target Tags.empty;
-      let st = sys_command cmd in
-      if st <> 0 then
-        failwith (Printf.sprintf "Error during command `%s'.\nExit code %d.\n" cmd st)
-      else
-        ()
-    end
-  else
-    match My_unix.execute_many ~ticker:Log.update ~display:Log.display [[(fun () -> cmd)]] with
-    | None -> ()
-    | Some(_, x) ->
-      failwith (Printf.sprintf "Error during command %S: %s" cmd (Printexc.to_string x))
+  match My_unix.execute_many ~ticker:Log.update ~display:Log.display [[(fun () -> cmd)]] with
+  | None -> ()
+  | Some(_, x) ->
+    failwith (Printf.sprintf "Error during command %S: %s" cmd (Printexc.to_string x))
 let rm = sys_remove
 let rm_f x =
   if sys_file_exists x then ()
@@ -69,7 +72,7 @@ let rm_f x =
 let mkdir dir =
   reset_filesys_cache_for_file dir;
   (*Sys.mkdir dir (* MISSING in ocaml *) *)
-  run ["mkdir"; dir] dir
+  run ["mkdir"; dir]
 
 let try_mkdir dir =
   if not (sys_file_exists dir)
@@ -95,7 +98,7 @@ let rec mkdir_p dir =
 
 let cp_pf src dest =
   reset_filesys_cache_for_file dest;
-  run["cp";"-pf";src;dest] dest
+  run["cp";"-pf";src;dest]
 
 (* Archive files are handled specially during copy *)
 let cp src dst =
@@ -109,9 +112,9 @@ let readlink = My_unix.readlink
 let is_link = My_unix.is_link
 let rm_rf x =
   reset_filesys_cache ();
-  run["rm";"-Rf";x] x
+  run["rm";"-Rf";x]
 let mv src dest =
   reset_filesys_cache_for_file src;
   reset_filesys_cache_for_file dest;
-  run["mv"; src; dest] dest
+  run["mv"; src; dest]
   (*Sys.rename src dest*)