editor = getenv("EDITOR");
    if (!editor)
      editor = "pico"; /* OK since editor won't be freed */

    cmd = malloc(sizeof(char) * strlen(editor) + 7);
    sprintf(cmd, "%s \"$1\"", editor);

    /* sh -c '$EDITOR "$1"' sh "$fn" */
    execlp("sh", "sh", "-c", cmd, "sh", fn, NULL);
    perror("Failed to execute editor");
    fprintf(stderr, "Make sure the EDITOR environment variable contains" 
                    " a valid editor\n");