diff --git a/main-runner.go b/main-runner.go
index c9b9fbe70..a74bcf034 100644
--- a/main-runner.go
+++ b/main-runner.go
@@ -127,7 +127,6 @@ func doMainRun(pk *packet.RunPacketType, sender *packet.PacketSender) {
 }
 
 func doGetCmd(tailer *cmdtail.Tailer, pk *packet.GetCmdPacketType, sender *packet.PacketSender) error {
-	// non-tail packets?
 	err := tailer.AddWatch(pk)
 	if err != nil {
 		return err
diff --git a/pkg/cmdtail/cmdtail.go b/pkg/cmdtail/cmdtail.go
index e09408697..b43e044d1 100644
--- a/pkg/cmdtail/cmdtail.go
+++ b/pkg/cmdtail/cmdtail.go
@@ -21,17 +21,52 @@ import (
 const MaxDataBytes = 4096
 
 type TailPos struct {
-	CmdKey     CmdKey
+	ReqId      string
 	Running    bool // an active tailer sending data
-	FilePtyLen int64
-	FileRunLen int64
 	TailPtyPos int64
 	TailRunPos int64
 	Follow     bool
 }
 
-func (pos TailPos) IsCurrent() bool {
-	return pos.TailPtyPos >= pos.FilePtyLen && pos.TailRunPos >= pos.FileRunLen
+type CmdWatchEntry struct {
+	CmdKey     CmdKey
+	FilePtyLen int64
+	FileRunLen int64
+	Tails      []TailPos
+}
+
+func (w CmdWatchEntry) getTailPos(reqId string) (TailPos, bool) {
+	for _, pos := range w.Tails {
+		if pos.ReqId == reqId {
+			return pos, true
+		}
+	}
+	return TailPos{}, false
+}
+
+func (w *CmdWatchEntry) updateTailPos(reqId string, pos TailPos) {
+	for idx, pos := range w.Tails {
+		if pos.ReqId == reqId {
+			w.Tails[idx] = pos
+			return
+		}
+	}
+	w.Tails = append(w.Tails, pos)
+}
+
+func (w *CmdWatchEntry) removeTailPos(reqId string) {
+	var newTails []TailPos
+	for _, pos := range w.Tails {
+		if pos.ReqId == reqId {
+			continue
+		}
+		newTails = append(newTails, pos)
+	}
+	w.Tails = newTails
+}
+
+func (pos TailPos) IsCurrent(entry CmdWatchEntry) bool {
+	return pos.TailPtyPos >= entry.FilePtyLen && pos.TailRunPos >= entry.FileRunLen
 }
 
 type CmdKey struct {
@@ -41,12 +76,43 @@ type CmdKey struct {
 
 type Tailer struct {
 	Lock      *sync.Mutex
-	WatchList map[CmdKey]TailPos
+	WatchList map[CmdKey]CmdWatchEntry
 	ScHomeDir string
 	Watcher   *SessionWatcher
 	SendCh    chan packet.PacketType
 }
 
+func (t *Tailer) updateTailPos_nolock(cmdKey CmdKey, reqId string, pos TailPos) {
+	entry, found := t.WatchList[cmdKey]
+	if !found {
+		return
+	}
+	entry.updateTailPos(reqId, pos)
+	t.WatchList[cmdKey] = entry
+}
+
+func (t *Tailer) updateEntrySizes_nolock(cmdKey CmdKey, ptyLen int64, runLen int64) {
+	entry, found := t.WatchList[cmdKey]
+	if !found {
+		return
+	}
+	entry.FilePtyLen = ptyLen
+	entry.FileRunLen = runLen
+	t.WatchList[cmdKey] = entry
+}
+
+func (t *Tailer) getEntryAndPos_nolock(cmdKey CmdKey, reqId string) (CmdWatchEntry, TailPos, bool) {
+	entry, found := t.WatchList[cmdKey]
+	if !found {
+		return CmdWatchEntry{}, TailPos{}, false
+	}
+	pos, found := entry.getTailPos(reqId)
+	if !found {
+		return CmdWatchEntry{}, TailPos{}, false
+	}
+	return entry, pos, true
+}
+
 func MakeTailer(sendCh chan packet.PacketType) (*Tailer, error) {
 	scHomeDir, err := base.GetScHomeDir()
 	if err != nil {
@@ -54,7 +120,7 @@ func MakeTailer(sendCh chan packet.PacketType) (*Tailer, error) {
 	}
 	rtn := &Tailer{
 		Lock:      &sync.Mutex{},
-		WatchList: make(map[CmdKey]TailPos),
+		WatchList: make(map[CmdKey]CmdWatchEntry),
 		ScHomeDir: scHomeDir,
 		SendCh:    sendCh,
 	}
@@ -79,45 +145,48 @@ func (t *Tailer) readDataFromFile(fileName string, pos int64, maxBytes int) ([]b
 	return buf[0:nr], nil
 }
 
-func (t *Tailer) makeCmdDataPacket(fileNames *base.CommandFileNames, pos TailPos) *packet.CmdDataPacketType {
+func (t *Tailer) makeCmdDataPacket(fileNames *base.CommandFileNames, entry CmdWatchEntry, pos TailPos) *packet.CmdDataPacketType {
 	dataPacket := packet.MakeCmdDataPacket()
-	dataPacket.SessionId = pos.CmdKey.SessionId
-	dataPacket.CmdId = pos.CmdKey.CmdId
+	dataPacket.ReqId = pos.ReqId
+	dataPacket.SessionId = entry.CmdKey.SessionId
+	dataPacket.CmdId = entry.CmdKey.CmdId
 	dataPacket.PtyPos = pos.TailPtyPos
 	dataPacket.RunPos = pos.TailRunPos
-	if pos.FilePtyLen > pos.TailPtyPos {
+	if entry.FilePtyLen > pos.TailPtyPos {
 		ptyData, err := t.readDataFromFile(fileNames.PtyOutFile, pos.TailPtyPos, MaxDataBytes)
 		if err != nil {
 			dataPacket.Error = err.Error()
 			return dataPacket
 		}
 		dataPacket.PtyData = string(ptyData)
+		dataPacket.PtyDataLen = len(ptyData)
 	}
-	if pos.FileRunLen > pos.TailRunPos {
+	if entry.FileRunLen > pos.TailRunPos {
 		runData, err := t.readDataFromFile(fileNames.RunnerOutFile, pos.TailRunPos, MaxDataBytes)
 		if err != nil {
 			dataPacket.Error = err.Error()
 			return dataPacket
 		}
 		dataPacket.RunData = string(runData)
+		dataPacket.RunDataLen = len(runData)
 	}
 	return dataPacket
 }
 
 // returns (data-packet, keepRunning)
-func (t *Tailer) runSingleDataTransfer(key CmdKey) (*packet.CmdDataPacketType, bool) {
+func (t *Tailer) runSingleDataTransfer(key CmdKey, reqId string) (*packet.CmdDataPacketType, bool) {
 	t.Lock.Lock()
-	pos, foundPos := t.WatchList[key]
+	entry, pos, foundPos := t.getEntryAndPos_nolock(key, reqId)
 	t.Lock.Unlock()
 	if !foundPos {
 		return nil, false
 	}
 	fileNames := base.MakeCommandFileNamesWithHome(t.ScHomeDir, key.SessionId, key.CmdId)
-	dataPacket := t.makeCmdDataPacket(fileNames, pos)
+	dataPacket := t.makeCmdDataPacket(fileNames, entry, pos)
 
 	t.Lock.Lock()
 	defer t.Lock.Unlock()
-	pos, foundPos = t.WatchList[key]
+	entry, pos, foundPos = t.getEntryAndPos_nolock(key, reqId)
 	if !foundPos {
 		return nil, false
 	}
@@ -128,45 +197,44 @@ func (t *Tailer) runSingleDataTransfer(key CmdKey) (*packet.CmdDataPacketType, b
 	if dataPacket.Error != "" {
 		// error, so return error packet, and stop running
 		pos.Running = false
-		t.WatchList[key] = pos
+		t.updateTailPos_nolock(key, reqId, pos)
 		return dataPacket, false
 	}
 	pos.TailPtyPos += int64(len(dataPacket.PtyData))
 	pos.TailRunPos += int64(len(dataPacket.RunData))
-	if pos.TailPtyPos > pos.FilePtyLen {
-		pos.FilePtyLen = pos.TailPtyPos
-	}
-	if pos.TailRunPos > pos.FileRunLen {
-		pos.FileRunLen = pos.TailRunPos
-	}
-	if pos.TailPtyPos >= pos.FilePtyLen && pos.TailRunPos >= pos.FileRunLen {
+	if pos.TailPtyPos >= entry.FilePtyLen && pos.TailRunPos >= entry.FileRunLen {
 		// we caught up, tail position equals file length
 		pos.Running = false
 	}
-	t.WatchList[key] = pos
+	t.updateTailPos_nolock(key, reqId, pos)
 	return dataPacket, pos.Running
 }
 
-func (t *Tailer) checkRemoveNoFollow(cmdKey CmdKey) {
+func (t *Tailer) checkRemoveNoFollow(cmdKey CmdKey, reqId string) {
 	t.Lock.Lock()
 	defer t.Lock.Unlock()
-	pos, foundPos := t.WatchList[cmdKey]
+	entry, pos, foundPos := t.getEntryAndPos_nolock(cmdKey, reqId)
 	if !foundPos {
 		return
 	}
 	if !pos.Follow {
-		delete(t.WatchList, cmdKey)
+		entry.removeTailPos(reqId)
+		if len(entry.Tails) == 0 {
+			delete(t.WatchList, cmdKey)
+		} else {
+			t.WatchList[cmdKey] = entry
+		}
 	}
 }
 
-func (t *Tailer) RunDataTransfer(key CmdKey) {
+func (t *Tailer) RunDataTransfer(key CmdKey, reqId string) {
 	for {
-		dataPacket, keepRunning := t.runSingleDataTransfer(key)
+		dataPacket, keepRunning := t.runSingleDataTransfer(key, reqId)
 		if dataPacket != nil {
 			t.SendCh <- dataPacket
 		}
 		if !keepRunning {
-			t.checkRemoveNoFollow(key)
+			t.checkRemoveNoFollow(key, reqId)
 			break
 		}
 		time.Sleep(10 * time.Millisecond)
@@ -174,13 +242,13 @@ func (t *Tailer) RunDataTransfer(key CmdKey) {
 }
 
 // should already hold t.Lock
-func (t *Tailer) tryStartRun_nolock(pos TailPos) {
-	if pos.Running || pos.IsCurrent() {
+func (t *Tailer) tryStartRun_nolock(entry CmdWatchEntry, pos TailPos) {
+	if pos.Running || pos.IsCurrent(entry) {
 		return
 	}
 	pos.Running = true
-	t.WatchList[pos.CmdKey] = pos
-	go t.RunDataTransfer(pos.CmdKey)
+	t.updateTailPos_nolock(entry.CmdKey, pos.ReqId, pos)
+	go t.RunDataTransfer(entry.CmdKey, pos.ReqId)
 }
 
 func (t *Tailer) updateFile(event FileUpdateEvent) {
@@ -191,17 +259,19 @@ func (t *Tailer) updateFile(event FileUpdateEvent) {
 	cmdKey := CmdKey{SessionId: event.SessionId, CmdId: event.CmdId}
 	t.Lock.Lock()
 	defer t.Lock.Unlock()
-	pos, foundPos := t.WatchList[cmdKey]
-	if !foundPos {
+	entry, foundEntry := t.WatchList[cmdKey]
+	if !foundEntry {
 		return
 	}
 	if event.FileType == FileTypePty {
-		pos.FilePtyLen = event.Size
+		entry.FilePtyLen = event.Size
 	} else if event.FileType == FileTypeRun {
-		pos.FileRunLen = event.Size
+		entry.FileRunLen = event.Size
+	}
+	t.WatchList[cmdKey] = entry
+	for _, pos := range entry.Tails {
+		t.tryStartRun_nolock(entry, pos)
 	}
-	t.WatchList[cmdKey] = pos
-	t.tryStartRun_nolock(pos)
 }
 
 func (t *Tailer) Run() error {
@@ -221,22 +291,15 @@ func max(v1 int64, v2 int64) int64 {
 	return v2
 }
 
-// also converts negative positions to positive positions
-func (tp *TailPos) fillFilePos(scHomeDir string) {
-	fileNames := base.MakeCommandFileNamesWithHome(scHomeDir, tp.CmdKey.SessionId, tp.CmdKey.CmdId)
+func (entry *CmdWatchEntry) fillFilePos(scHomeDir string) {
+	fileNames := base.MakeCommandFileNamesWithHome(scHomeDir, entry.CmdKey.SessionId, entry.CmdKey.CmdId)
 	ptyInfo, _ := os.Stat(fileNames.PtyOutFile)
 	if ptyInfo != nil {
-		tp.FilePtyLen = ptyInfo.Size()
-	}
-	if tp.TailPtyPos < 0 {
-		tp.TailPtyPos = max(0, tp.FilePtyLen-tp.TailPtyPos)
+		entry.FilePtyLen = ptyInfo.Size()
 	}
 	runoutInfo, _ := os.Stat(fileNames.RunnerOutFile)
 	if runoutInfo != nil {
-		tp.FileRunLen = runoutInfo.Size()
-	}
-	if tp.TailRunPos < 0 {
-		tp.TailRunPos = max(0, tp.FileRunLen-tp.TailRunPos)
+		entry.FileRunLen = runoutInfo.Size()
 	}
 }
 
@@ -252,6 +315,9 @@ func (t *Tailer) AddWatch(getPacket *packet.GetCmdPacketType) error {
 	if err != nil {
 		return fmt.Errorf("getcmd, bad cmdid '%s': %w", getPacket.CmdId, err)
 	}
+	if getPacket.ReqId == "" {
+		return fmt.Errorf("getcmd, no reqid specified")
+	}
 	t.Lock.Lock()
 	defer t.Lock.Unlock()
 	key := CmdKey{getPacket.SessionId, getPacket.CmdId}
@@ -259,9 +325,21 @@ func (t *Tailer) AddWatch(getPacket *packet.GetCmdPacketType) error {
 	if err != nil {
 		return fmt.Errorf("error trying to watch sesion '%s': %v", getPacket.SessionId, err)
 	}
-	pos := TailPos{CmdKey: key, TailPtyPos: getPacket.PtyPos, TailRunPos: getPacket.RunPos, Follow: getPacket.Tail}
-	pos.fillFilePos(t.ScHomeDir)
-	t.WatchList[key] = pos
-	t.tryStartRun_nolock(pos)
+	entry, foundEntry := t.WatchList[key]
+	if !foundEntry {
+		entry = CmdWatchEntry{CmdKey: key}
+		entry.fillFilePos(t.ScHomeDir)
+	}
+	pos := TailPos{ReqId: getPacket.ReqId, TailPtyPos: getPacket.PtyPos, TailRunPos: getPacket.RunPos, Follow: getPacket.Tail}
+	// convert negative pos to positive
+	if pos.TailPtyPos < 0 {
+		pos.TailPtyPos = max(0, entry.FilePtyLen+pos.TailPtyPos) // + because negative
+	}
+	if pos.TailRunPos < 0 {
+		pos.TailRunPos = max(0, entry.FileRunLen+pos.TailRunPos) // + because negative
+	}
+	entry.updateTailPos(pos.ReqId, pos)
+	t.WatchList[key] = entry
+	t.tryStartRun_nolock(entry, pos)
 	return nil
 }
diff --git a/pkg/packet/packet.go b/pkg/packet/packet.go
index 78f77cb02..dec400665 100644
--- a/pkg/packet/packet.go
+++ b/pkg/packet/packet.go
@@ -27,6 +27,7 @@ const CmdStartPacketStr = "cmdstart"
 const CmdDonePacketStr = "cmddone"
 const ListCmdPacketStr = "lscmd"
 const GetCmdPacketStr = "getcmd"
+const UntailCmdPacketStr = "untailcmd"
 const RunnerInitPacketStr = "runnerinit"
 const CdPacketStr = "cd"
 const CdResponseStr = "cdresp"
@@ -46,6 +47,7 @@ func init() {
 	TypeStrToFactory[CmdDonePacketStr] = reflect.TypeOf(CmdDonePacketType{})
 	TypeStrToFactory[ListCmdPacketStr] = reflect.TypeOf(ListCmdPacketType{})
 	TypeStrToFactory[GetCmdPacketStr] = reflect.TypeOf(GetCmdPacketType{})
+	TypeStrToFactory[UntailCmdPacketStr] = reflect.TypeOf(UntailCmdPacketType{})
 	TypeStrToFactory[RunnerInitPacketStr] = reflect.TypeOf(RunnerInitPacketType{})
 	TypeStrToFactory[CdPacketStr] = reflect.TypeOf(CdPacketType{})
 	TypeStrToFactory[CdResponseStr] = reflect.TypeOf(CdResponseType{})
@@ -63,17 +65,20 @@ func MakePacket(packetType string) (PacketType, error) {
 }
 
 type CmdDataPacketType struct {
-	Type      string `json:"type"`
-	SessionId string `json:"sessionid"`
-	CmdId     string `json:"cmdid"`
-	PtyPos    int64  `json:"ptypos"`
-	PtyLen    int64  `json:"ptylen"`
-	RunPos    int64  `json:"runpos"`
-	RunLen    int64  `json:"runlen"`
-	PtyData   string `json:"ptydata"`
-	RunData   string `json:"rundata"`
-	Error     string `json:"error"`
-	NotFound  bool   `json:"notfound,omitempty"`
+	Type       string `json:"type"`
+	ReqId      string `json:"reqid"`
+	SessionId  string `json:"sessionid"`
+	CmdId      string `json:"cmdid"`
+	PtyPos     int64  `json:"ptypos"`
+	PtyLen     int64  `json:"ptylen"`
+	RunPos     int64  `json:"runpos"`
+	RunLen     int64  `json:"runlen"`
+	PtyData    string `json:"ptydata"`
+	PtyDataLen int    `json:"ptydatalen"`
+	RunData    string `json:"rundata"`
+	RunDataLen int    `json:"rundatalen"`
+	Error      string `json:"error"`
+	NotFound   bool   `json:"notfound,omitempty"`
 }
 
 func (*CmdDataPacketType) GetType() string {
@@ -96,8 +101,24 @@ func MakePingPacket() *PingPacketType {
 	return &PingPacketType{Type: PingPacketStr}
 }
 
+type UntailCmdPacketType struct {
+	Type      string `json:"type"`
+	ReqId     string `json:"reqid"`
+	SessionId string `json:"sessionid"`
+	CmdId     string `json:"cmdid"`
+}
+
+func (*UntailCmdPacketType) GetType() string {
+	return UntailCmdPacketStr
+}
+
+func MakeUntailCmdPacket() *UntailCmdPacketType {
+	return &UntailCmdPacketType{Type: UntailCmdPacketStr}
+}
+
 type GetCmdPacketType struct {
 	Type      string `json:"type"`
+	ReqId     string `json:"reqid"`
 	SessionId string `json:"sessionid"`
 	CmdId     string `json:"cmdid"`
 	PtyPos    int64  `json:"ptypos"`