static int backtick_exitValue;
static boolean backtick_verbose, backtick_keepScript;
static new ThreadLocal<File> backtick_scriptFile;
static new ThreadLocal<Bool> backtick_uninterruptable; // Great trick, thanks to Tim Bunce @ http://stackoverflow.com/questions/12856620/how-to-handle-signals-in-bash-during-synchronous-execution

sbool backtick_win_cmd; // bugfixing

static String backtick(String cmd) ctex {
  ping();
  File outFile = File.createTempFile("_backtick", "");
  backtickToFile(cmd, outFile);
  S result = loadTextFile(outFile.getPath(), "");
  if (backtick_verbose) {
    //print("backtick: script length after=" + backtick_scriptFile->length());
    print("[[\n" + result + "]]");
  }
  outFile.delete();
  ret result;
}

static java.lang.Process backtickToFile(String cmd, File outFile) ctex {
  try {
    java.lang.Process process = backtickToFile_noWait(cmd, outFile);
    process.waitFor();
    backtick_exitValue = process.exitValue();
    if (backtick_verbose)
      System.out.println("Process return code: " + backtick_exitValue);
    ret process;
  } finally {
    if (!backtick_keepScript)
      deleteFile(backtick_scriptFile.get());
    backtick_scriptFile.set(null);
  }
}

static java.lang.Process backtickToFile_noWait(String cmd, File outFile) ctex {
  ping();
  File scriptFile;
  S ext = isWindows() ? ".bat" : "";
  if (backtick_keepScript)
    scriptFile = makeFileNameUnique_withExtension(javaxCachesDir("Cmd Scripts/backtick"), ".bat");
  else
    scriptFile = File.createTempFile("_backtick", ext);
  backtick_scriptFile.set(scriptFile);
  if (backtick_verbose)
    print("backtick: scriptFile " + f2s(scriptFile));
    
  bool makeInterruptable = !isTrue(backtick_uninterruptable!) && !isWindows();

  cmd = trim(cmd);
  if (makeInterruptable && numLines(cmd) > 1) fail("No multi-line commands allowed when making interruptable");
  
  S command = cmd + " >" + bashQuote(outFile.getPath()) + " 2>&1";
  if (makeInterruptable) command = fixNewLines([[
interruptable() {

    # handle options
    local setsid=""
    local debug=false
    while true; do
        case "${1:-}" in
            --killall)      setsid=setsid; shift ;;
            --debug)        debug=true; shift ;;
            --*)            echo "Invalid option: $1" 1>&2; exit 1;;
            *)              break;; # no more options
        esac
    done

    # start the specified command
    $setsid "$@" &
    local child_pid=$!

    # arrange to propagate a signal to the child process
    trap '
        exec 1>&2
        set +e
        trap "" SIGPIPE # ensure a possible sigpipe from the echo does not prevent the kill
        echo "${BASH_SOURCE[0]} caught SIGTERM while executing $* (pid $child_pid), sending SIGTERM to it"
        # (race) child may have exited in which case kill will report an error
        # if setsid is used then prefix the pid with a "-" to indicate that the signal
        # should be sent to the entire process group
        kill ${setsid:+-}$child_pid
        exit 143
    ' SIGTERM
    # ensure that the trap doesn't persist after we return
    trap 'trap - SIGTERM' RETURN

    $debug && echo "interruptable wait (child $child_pid, self $$) for: $*"

    # An error status from the child process will trigger an exception (via set -e)
    # here unless the caller is checking the return status
    wait $child_pid # last command, so status of waited for command is returned
}

interruptable ]]) + command;
  //Log.info("[Backtick] " + command);
  if (backtick_verbose) {
    print("backtick: command " + command);
    print("backtick: saving to " + scriptFile.getPath());
  }
  saveTextFile(scriptFile.getPath(), command);
  if (backtick_verbose)
    print("backtick: command length=" + l(command) + ", file length=" + scriptFile.length());
  String[] command2;
  if (isWindows())
    if (backtick_win_cmd)
      command2 = new S[] { "cmd", "/c", scriptFile.getPath() };
    else
      command2 = new S[] { scriptFile.getPath() };
  else
    command2 = new String[] { "/bin/bash", scriptFile.getPath() };
  if (backtick_verbose)
    print("backtick: command2 " + structure(command2));
  ret Runtime.getRuntime().exec(command2);
}