fix: commands on SSH hosts run under sh -c, so hosts whose login shell is csh or tcsh list, zip and send files too

internal/agent/sshfs.go

@@ -246,7 +246,7 @@ func (a *Agent) sshfsRun(c *sshfsConn, cmd string, stdin io.Reader) ([]byte, err
 	if stdin != nil {
 		s.Stdin = stdin
 	}
-	if err := s.Run(cmd); err != nil {
+	if err := s.Run(posix(cmd)); err != nil {
 		msg := strings.TrimSpace(errb.String())
 		if msg == "" {
 			msg = err.Error()
@@ -535,7 +535,7 @@ func (a *Agent) doSSHFSSend(ctx context.Context, env proto.TaskEnvelope) proto.T
 	}
 	defer s.Close()
 	out, _ := s.StdoutPipe()
-	if err := s.Start("cat -- " + shq(args.Path)); err != nil {
+	if err := s.Start(posix("cat -- " + shq(args.Path))); err != nil {
 		return proto.TaskResult{Error: err.Error()}
 	}
 	// Read in order from cat, posted to the server a few at a time.
@@ -612,7 +612,7 @@ func (a *Agent) doSSHFSPut(ctx context.Context, env proto.TaskEnvelope) proto.Ta
 	in, _ := s.StdinPipe()
 	var errb bytes.Buffer
 	s.Stderr = &limitBuf{b: &errb, max: 4096}
-	if err := s.Start(writeCommand(args.Path)); err != nil {
+	if err := s.Start(posix(writeCommand(args.Path))); err != nil {
 		return proto.TaskResult{Error: err.Error()}
 	}
 	// Pieces come in a few ahead; stdin takes them in order. ack: how many
@@ -711,7 +711,7 @@ func (a *Agent) packRemote(ctx context.Context, w io.Writer, c *sshfsConn, srcs,
 		rename[b] = names[i]
 		cmd += " " + shq(b)
 	}
-	if err := s.Start(cmd); err != nil {
+	if err := s.Start(posix(cmd)); err != nil {
 		return err
 	}
 	if err := renameTar(w, &countReader{r: out, n: &m.done}, rename); err != nil {