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);

}