diff --git a/main-runner.go b/main-runner.go
index 04fb9f4a6..19b0ba3c2 100644
--- a/main-runner.go
+++ b/main-runner.go
@@ -11,23 +11,30 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
 
+	"github.com/google/uuid"
+	"github.com/scripthaus-dev/sh2-runner/pkg/base"
 	"github.com/scripthaus-dev/sh2-runner/pkg/packet"
 	"github.com/scripthaus-dev/sh2-runner/pkg/shexec"
 )
 
-func setupSignals(cmd *shexec.ShExecType) {
+// in single run mode, we don't want the runner to die from signals
+// since we want the single runner to persist even if session / main runner
+// is terminated.
+func setupSingleSignals(cmd *shexec.ShExecType) {
 	sigCh := make(chan os.Signal, 1)
-	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
 	go func() {
-		for sig := range sigCh {
-			cmd.Cmd.Process.Signal(sig)
+		for range sigCh {
+			// do nothing
 		}
 	}()
 }
 
-func main() {
+func doSingle(cmdId string) {
 	packetCh := packet.PacketParser(os.Stdin)
+	sender := packet.MakePacketSender(os.Stdout)
 	var runPacket *packet.RunPacketType
 	for pk := range packetCh {
 		if pk.GetType() == packet.PingPacketStr {
@@ -37,24 +44,134 @@ func main() {
 			runPacket, _ = pk.(*packet.RunPacketType)
 			break
 		}
-		if pk.GetType() == packet.ErrorPacketStr {
-			packet.SendPacket(os.Stdout, pk)
-			return
-		}
-		packet.SendErrorPacket(os.Stdout, fmt.Sprintf("invalid packet '%s' sent to runner", pk.GetType()))
+		sender.SendErrorPacket(fmt.Sprintf("invalid packet '%s' sent to runner", pk.GetType()))
 		return
 	}
 	if runPacket == nil {
-		packet.SendErrorPacket(os.Stdout, "did not receive a 'run' packet")
+		sender.SendErrorPacket("did not receive a 'run' packet")
 		return
 	}
-	cmd, err := shexec.RunCommand(runPacket)
+	if runPacket.CmdId == "" {
+		runPacket.CmdId = cmdId
+	}
+	if runPacket.CmdId != cmdId {
+		sender.SendErrorPacket(fmt.Sprintf("run packet cmdid[%s] did not match arg[%s]", runPacket.CmdId, cmdId))
+		return
+	}
+	cmd, err := shexec.RunCommand(runPacket, sender)
 	if err != nil {
-		packet.SendErrorPacket(os.Stdout, fmt.Sprintf("error running command: %v", err))
+		sender.SendErrorPacket(fmt.Sprintf("error running command: %v", err))
 		return
 	}
-	setupSignals(cmd)
-	packet.SendPacket(os.Stdout, packet.MakeOkCmdPacket(fmt.Sprintf("running command %s/%s", runPacket.SessionId, runPacket.CmdId), runPacket.CmdId, cmd.Cmd.Process.Pid))
-	cmd.WaitForCommand()
-	packet.SendPacket(os.Stdout, packet.MakeDonePacket())
+	setupSingleSignals(cmd)
+	startPacket := packet.MakeCmdStartPacket()
+	startPacket.Ts = time.Now().UnixMilli()
+	startPacket.CmdId = runPacket.CmdId
+	startPacket.Pid = cmd.Cmd.Process.Pid
+	startPacket.RunnerPid = os.Getpid()
+	sender.SendPacket(startPacket)
+	donePacket := cmd.WaitForCommand(runPacket.CmdId)
+	sender.SendPacket(donePacket)
+	sender.CloseSendCh()
+	sender.WaitForDone()
+}
+
+func doMainRun(pk *packet.RunPacketType, sender *packet.PacketSender) {
+	if pk.CmdId == "" {
+		pk.CmdId = uuid.New().String()
+	}
+	err := shexec.ValidateRunPacket(pk)
+	if err != nil {
+		sender.SendPacket(packet.MakeIdErrorPacket(pk.CmdId, fmt.Sprintf("invalid run packet: %v", err)))
+		return
+	}
+	fileNames, err := base.GetCommandFileNames(pk.SessionId, pk.CmdId)
+	if err != nil {
+		sender.SendPacket(packet.MakeIdErrorPacket(pk.CmdId, fmt.Sprintf("cannot get command file names: %v", err)))
+		return
+	}
+	cmd, err := shexec.MakeRunnerExec(pk.CmdId)
+	if err != nil {
+		sender.SendPacket(packet.MakeIdErrorPacket(pk.CmdId, fmt.Sprintf("cannot make runner command: %v", err)))
+		return
+	}
+	cmdStdin, err := cmd.StdinPipe()
+	if err != nil {
+		sender.SendPacket(packet.MakeIdErrorPacket(pk.CmdId, fmt.Sprintf("cannot pipe stdin to command: %v", err)))
+		return
+	}
+	runnerOutFd, err := os.OpenFile(fileNames.RunnerOutFile, os.O_CREATE|os.O_TRUNC|os.O_APPEND|os.O_WRONLY, 0600)
+	if err != nil {
+		sender.SendPacket(packet.MakeIdErrorPacket(pk.CmdId, fmt.Sprintf("cannot open runner out file '%s': %v", fileNames.RunnerOutFile, err)))
+		return
+	}
+	cmd.Stdout = runnerOutFd
+	cmd.Stderr = runnerOutFd
+	err = cmd.Start()
+	if err != nil {
+		sender.SendPacket(packet.MakeIdErrorPacket(pk.CmdId, fmt.Sprintf("error starting command: %v", err)))
+		return
+	}
+	go func() {
+		err = packet.SendPacket(cmdStdin, pk)
+		if err != nil {
+			sender.SendPacket(packet.MakeIdErrorPacket(pk.CmdId, fmt.Sprintf("error sending forked runner command: %v", err)))
+			return
+		}
+		cmdStdin.Close()
+
+		// clean up zombies
+		cmd.Wait()
+	}()
+}
+
+func doMain() {
+	homeDir, err := base.GetScHomeDir()
+	if err != nil {
+		packet.SendErrorPacket(os.Stdout, err.Error())
+		return
+	}
+	err = os.Chdir(homeDir)
+	if err != nil {
+		packet.SendErrorPacket(os.Stdout, fmt.Sprintf("cannot change directory to scripthaus home '%s': %v", homeDir, err))
+		return
+	}
+	err = base.EnsureRunnerPath()
+	if err != nil {
+		packet.SendErrorPacket(os.Stdout, err.Error())
+		return
+	}
+	packetCh := packet.PacketParser(os.Stdin)
+	sender := packet.MakePacketSender(os.Stdout)
+	sender.SendPacket(packet.MakeMessagePacket(fmt.Sprintf("starting scripthaus runner @ %s", homeDir)))
+	for pk := range packetCh {
+		if pk.GetType() == packet.PingPacketStr {
+			continue
+		}
+		if pk.GetType() == packet.RunPacketStr {
+			doMainRun(pk.(*packet.RunPacketType), sender)
+			continue
+		}
+		if pk.GetType() == packet.ErrorPacketStr {
+			errPk := pk.(*packet.ErrorPacketType)
+			errPk.Error = "invalid packet sent to runner: " + errPk.Error
+			sender.SendPacket(errPk)
+			continue
+		}
+		sender.SendErrorPacket(fmt.Sprintf("invalid packet '%s' sent to runner", pk.GetType()))
+	}
+}
+
+func main() {
+	if len(os.Args) >= 2 {
+		cmdId, err := uuid.Parse(os.Args[1])
+		if err != nil {
+			packet.SendErrorPacket(os.Stdout, fmt.Sprintf("invalid non-cmdid passed to runner", err))
+			return
+		}
+		doSingle(cmdId.String())
+		return
+	} else {
+		doMain()
+	}
 }
diff --git a/pkg/base/base.go b/pkg/base/base.go
index ae6774cec..fd2d64ed0 100644
--- a/pkg/base/base.go
+++ b/pkg/base/base.go
@@ -27,9 +27,9 @@ const ScReadyString = "scripthaus runner ready"
 const OSCEscError = "error"
 
 type CommandFileNames struct {
-	PtyOutFile string
-	StdinFifo  string
-	DoneFile   string
+	PtyOutFile    string
+	StdinFifo     string
+	RunnerOutFile string
 }
 
 func GetScHomeDir() (string, error) {
@@ -54,9 +54,9 @@ func GetCommandFileNames(sessionId string, cmdId string) (*CommandFileNames, err
 	}
 	base := path.Join(sdir, cmdId)
 	return &CommandFileNames{
-		PtyOutFile: base + ".ptyout",
-		StdinFifo:  base + ".stdin",
-		DoneFile:   base + ".done",
+		PtyOutFile:    base + ".ptyout",
+		StdinFifo:     base + ".stdin",
+		RunnerOutFile: base + ".runout",
 	}, nil
 }
 
@@ -108,32 +108,50 @@ func EnsureSessionDir(sessionId string) (string, error) {
 	return sdir, nil
 }
 
-func GetScRunnerPath() string {
+func GetScRunnerPath() (string, error) {
 	runnerPath := os.Getenv(ScRunnerVarName)
 	if runnerPath != "" {
-		return runnerPath
+		return runnerPath, nil
 	}
 	scHome, err := GetScHomeDir()
 	if err != nil {
-		panic(err)
+		return "", err
 	}
-	return path.Join(scHome, RunnerBaseName)
+	return path.Join(scHome, RunnerBaseName), nil
 }
 
-func GetScSessionsDir() string {
-	scHome, err := GetScHomeDir()
+func EnsureRunnerPath() error {
+	runnerPath, err := GetScRunnerPath()
 	if err != nil {
-		panic(err)
+		return err
 	}
-	return path.Join(scHome, SessionsDirBaseName)
+	info, err := os.Stat(runnerPath)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return fmt.Errorf("cannot find scripthaus runner at path '%s'", runnerPath)
+		}
+		return fmt.Errorf("error stating scripthaus runner at path '%s'", runnerPath)
+	}
+	if info.Mode()&0100 == 0 {
+		return fmt.Errorf("scripthaus runner at path '%s' is not executable mode=%#o", runnerPath, info.Mode())
+	}
+	return nil
 }
 
-func GetSessionDBName(sessionId string) string {
+func GetScSessionsDir() (string, error) {
 	scHome, err := GetScHomeDir()
 	if err != nil {
-		panic(err)
+		return "", err
 	}
-	return path.Join(scHome, SessionDBName)
+	return path.Join(scHome, SessionsDirBaseName), nil
+}
+
+func GetSessionDBName(sessionId string) (string, error) {
+	scHome, err := GetScHomeDir()
+	if err != nil {
+		return "", err
+	}
+	return path.Join(scHome, SessionDBName), nil
 }
 
 // SH OSC Escapes (code 198, S=19, H=8)
diff --git a/pkg/packet/packet.go b/pkg/packet/packet.go
index 52e3a0da7..623284673 100644
--- a/pkg/packet/packet.go
+++ b/pkg/packet/packet.go
@@ -11,13 +11,16 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"sync"
 )
 
 const RunPacketStr = "run"
 const PingPacketStr = "ping"
 const DonePacketStr = "done"
 const ErrorPacketStr = "error"
-const OkCmdPacketStr = "okcmd"
+const MessagePacketStr = "message"
+const CmdStartPacketStr = "cmdstart"
+const CmdDonePacketStr = "cmddone"
 
 type PingPacketType struct {
 	Type string `json:"type"`
@@ -31,6 +34,19 @@ func MakePingPacket() *PingPacketType {
 	return &PingPacketType{Type: PingPacketStr}
 }
 
+type MessagePacketType struct {
+	Type    string `json:"type"`
+	Message string `json:"message"`
+}
+
+func (*MessagePacketType) GetType() string {
+	return MessagePacketStr
+}
+
+func MakeMessagePacket(message string) *MessagePacketType {
+	return &MessagePacketType{Type: MessagePacketStr, Message: message}
+}
+
 type DonePacketType struct {
 	Type string `json:"type"`
 }
@@ -43,27 +59,44 @@ func MakeDonePacket() *DonePacketType {
 	return &DonePacketType{Type: DonePacketStr}
 }
 
-type OkCmdPacketType struct {
-	Type    string `json:"type"`
-	Message string `json:"message"`
-	CmdId   string `json:"cmdid"`
-	Pid     int    `json:"pid"`
+type CmdDonePacketType struct {
+	Type       string `json:"type"`
+	Ts         int64  `json:"ts"`
+	CmdId      string `json:"cmdid"`
+	ExitCode   int    `json:"exitcode"`
+	DurationMs int64  `json:"durationms"`
 }
 
-func (*OkCmdPacketType) GetType() string {
-	return OkCmdPacketStr
+func (*CmdDonePacketType) GetType() string {
+	return CmdDonePacketStr
 }
 
-func MakeOkCmdPacket(message string, cmdId string, pid int) *OkCmdPacketType {
-	return &OkCmdPacketType{Type: OkCmdPacketStr, Message: message, CmdId: cmdId, Pid: pid}
+func MakeCmdDonePacket() *CmdDonePacketType {
+	return &CmdDonePacketType{Type: CmdDonePacketStr}
+}
+
+type CmdStartPacketType struct {
+	Type      string `json:"type"`
+	Ts        int64  `json:"ts"`
+	CmdId     string `json:"cmdid"`
+	Pid       int    `json:"pid"`
+	RunnerPid int    `json:"runnerpid"`
+}
+
+func (*CmdStartPacketType) GetType() string {
+	return CmdStartPacketStr
+}
+
+func MakeCmdStartPacket() *CmdStartPacketType {
+	return &CmdStartPacketType{Type: CmdStartPacketStr}
 }
 
 type RunPacketType struct {
 	Type      string            `json:"type"`
 	SessionId string            `json:"sessionid"`
 	CmdId     string            `json:"cmdid"`
-	ChDir     string            `json:"chdir"`
-	Env       map[string]string `json:"env"`
+	ChDir     string            `json:"chdir,omitempty"`
+	Env       map[string]string `json:"env,omitempty"`
 	Command   string            `json:"command"`
 }
 
@@ -76,6 +109,7 @@ type BarePacketType struct {
 }
 
 type ErrorPacketType struct {
+	Id    string `json:"id,omitempty"`
 	Type  string `json:"type"`
 	Error string `json:"error"`
 }
@@ -88,6 +122,10 @@ func MakeErrorPacket(errorStr string) *ErrorPacketType {
 	return &ErrorPacketType{Type: ErrorPacketStr, Error: errorStr}
 }
 
+func MakeIdErrorPacket(id string, errorStr string) *ErrorPacketType {
+	return &ErrorPacketType{Type: ErrorPacketStr, Id: id, Error: errorStr}
+}
+
 type PacketType interface {
 	GetType() string
 }
@@ -123,13 +161,21 @@ func ParseJsonPacket(jsonBuf []byte) (PacketType, error) {
 		}
 		return &errorPacket, nil
 	}
-	if bareCmd.Type == OkCmdPacketStr {
-		var okPacket OkCmdPacketType
-		err = json.Unmarshal(jsonBuf, &okPacket)
+	if bareCmd.Type == CmdStartPacketStr {
+		var startPacket CmdStartPacketType
+		err = json.Unmarshal(jsonBuf, &startPacket)
 		if err != nil {
 			return nil, err
 		}
-		return &okPacket, nil
+		return &startPacket, nil
+	}
+	if bareCmd.Type == CmdDonePacketStr {
+		var donePacket CmdDonePacketType
+		err = json.Unmarshal(jsonBuf, &donePacket)
+		if err != nil {
+			return nil, err
+		}
+		return &donePacket, nil
 	}
 	return nil, fmt.Errorf("invalid packet-type '%s'", bareCmd.Type)
 }
@@ -154,6 +200,73 @@ func SendErrorPacket(w io.Writer, errorStr string) error {
 	return SendPacket(w, MakeErrorPacket(errorStr))
 }
 
+type PacketSender struct {
+	Lock   *sync.Mutex
+	SendCh chan PacketType
+	Err    error
+	Done   bool
+	DoneCh chan bool
+}
+
+func MakePacketSender(output io.Writer) *PacketSender {
+	sender := &PacketSender{
+		Lock:   &sync.Mutex{},
+		SendCh: make(chan PacketType),
+		DoneCh: make(chan bool),
+	}
+	go func() {
+		defer func() {
+			sender.Lock.Lock()
+			sender.Done = true
+			sender.Lock.Unlock()
+			close(sender.DoneCh)
+		}()
+		for pk := range sender.SendCh {
+			err := SendPacket(output, pk)
+			if err != nil {
+				sender.Lock.Lock()
+				sender.Err = err
+				sender.Lock.Unlock()
+				return
+			}
+		}
+	}()
+	return sender
+}
+
+func (sender *PacketSender) CloseSendCh() {
+	close(sender.SendCh)
+}
+
+func (sender *PacketSender) WaitForDone() {
+	<-sender.DoneCh
+}
+
+func (sender *PacketSender) checkStatus() error {
+	sender.Lock.Lock()
+	defer sender.Lock.Unlock()
+	if sender.Done {
+		return fmt.Errorf("cannot send packet, sender write loop is closed")
+	}
+	if sender.Err != nil {
+		return fmt.Errorf("cannot send packet, sender had error: %w", sender.Err)
+	}
+	return nil
+}
+
+func (sender *PacketSender) SendPacket(pk PacketType) error {
+	err := sender.checkStatus()
+	if err != nil {
+		return err
+	}
+	sender.SendCh <- pk
+	return nil
+}
+
+func (sender *PacketSender) SendErrorPacket(errVal string) error {
+	return sender.SendPacket(MakeErrorPacket(errVal))
+}
+
 func PacketParser(input io.Reader) chan PacketType {
 	bufReader := bufio.NewReader(input)
 	rtnCh := make(chan PacketType)
diff --git a/pkg/shexec/shexec.go b/pkg/shexec/shexec.go
index 4ef5f6607..70e75f1d4 100644
--- a/pkg/shexec/shexec.go
+++ b/pkg/shexec/shexec.go
@@ -7,7 +7,6 @@
 package shexec
 
 import (
-	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -24,11 +23,6 @@ import (
 	"github.com/scripthaus-dev/sh2-runner/pkg/packet"
 )
 
-type DoneData struct {
-	DurationMs int64 `json:"durationms"`
-	ExitCode   int   `json:"exitcode"`
-}
-
 type ShExecType struct {
 	FileNames *base.CommandFileNames
 	Cmd       *exec.Cmd
@@ -95,6 +89,15 @@ func MakeExecCmd(pk *packet.RunPacketType, cmdTty *os.File) *exec.Cmd {
 	return ecmd
 }
 
+func MakeRunnerExec(cmdId string) (*exec.Cmd, error) {
+	runnerPath, err := base.GetScRunnerPath()
+	if err != nil {
+		return nil, err
+	}
+	ecmd := exec.Command(runnerPath, cmdId)
+	return ecmd, nil
+}
+
 // this will never return (unless there is an error creating/opening the file), as fifoFile will never EOF
 func MakeAndCopyStdinFifo(dst *os.File, fifoName string) error {
 	os.Remove(fifoName)
@@ -147,8 +150,8 @@ func ValidateRunPacket(pk *packet.RunPacketType) error {
 	return nil
 }
 
-// returning nil error means the process has successfully been kicked-off
-func RunCommand(pk *packet.RunPacketType) (*ShExecType, error) {
+// when err is nil, the command will have already been started
+func RunCommand(pk *packet.RunPacketType, sender *packet.PacketSender) (*ShExecType, error) {
 	if pk.CmdId == "" {
 		pk.CmdId = uuid.New().String()
 	}
@@ -184,14 +187,14 @@ func RunCommand(pk *packet.RunPacketType) (*ShExecType, error) {
 		// copy pty output to .ptyout file
 		_, copyErr := io.Copy(ptyOutFd, cmdPty)
 		if copyErr != nil {
-			base.WriteErrorMsg(fileNames.PtyOutFile, fmt.Sprintf("copying pty output to ptyout file: %v", copyErr))
+			sender.SendErrorPacket(fmt.Sprintf("copying pty output to ptyout file: %v", copyErr))
 		}
 	}()
 	go func() {
 		// copy .stdin fifo contents to pty input
 		copyFifoErr := MakeAndCopyStdinFifo(cmdPty, fileNames.StdinFifo)
 		if copyFifoErr != nil {
-			base.WriteErrorMsg(fileNames.PtyOutFile, fmt.Sprintf("reading from stdin fifo: %v", copyFifoErr))
+			sender.SendErrorPacket(fmt.Sprintf("reading from stdin fifo: %v", copyFifoErr))
 		}
 	}()
 	return &ShExecType{
@@ -202,9 +205,10 @@ func RunCommand(pk *packet.RunPacketType) (*ShExecType, error) {
 	}, nil
 }
 
-func (c *ShExecType) WaitForCommand() {
+func (c *ShExecType) WaitForCommand(cmdId string) *packet.CmdDonePacketType {
 	err := c.Cmd.Wait()
-	cmdDuration := time.Since(c.StartTs)
+	endTs := time.Now()
+	cmdDuration := endTs.Sub(c.StartTs)
 	exitCode := 0
 	if err != nil {
 		exitErr, ok := err.(*exec.ExitError)
@@ -212,15 +216,11 @@ func (c *ShExecType) WaitForCommand() {
 			exitCode = exitErr.ExitCode()
 		}
 	}
-	doneData := DoneData{
-		DurationMs: int64(cmdDuration / time.Millisecond),
-		ExitCode:   exitCode,
-	}
-	doneDataBytes, _ := json.Marshal(doneData)
-	doneDataBytes = append(doneDataBytes, '\n')
-	err = os.WriteFile(c.FileNames.DoneFile, doneDataBytes, 0600)
-	if err != nil {
-		base.WriteErrorMsg(c.FileNames.PtyOutFile, fmt.Sprintf("reading from stdin fifo: %v", err))
-	}
-	return
+	donePacket := packet.MakeCmdDonePacket()
+	donePacket.Ts = endTs.UnixMilli()
+	donePacket.CmdId = cmdId
+	donePacket.ExitCode = exitCode
+	donePacket.DurationMs = int64(cmdDuration / time.Millisecond)
+	os.Remove(c.FileNames.StdinFifo) // best effort (no need to check error)
+	return donePacket
 }