diff --git a/waveshell/pkg/shellapi/bashapi.go b/waveshell/pkg/shellapi/bashapi.go
index d2cbedfa0..8f1d18126 100644
--- a/waveshell/pkg/shellapi/bashapi.go
+++ b/waveshell/pkg/shellapi/bashapi.go
@@ -6,6 +6,7 @@ package shellapi
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"os/exec"
 	"runtime"
@@ -266,6 +267,22 @@ func (bashShellApi) MakeShellStateDiff(oldState *packet.ShellState, oldStateHash
 	return rtn, nil
 }
 
+func (bashShellApi) ValidateCommandSyntax(cmdStr string) error {
+	ctx, cancelFn := context.WithTimeout(context.Background(), ValidateTimeout)
+	defer cancelFn()
+	cmd := exec.CommandContext(ctx, GetLocalBashPath(), "-n", "-c", cmdStr)
+	output, err := cmd.CombinedOutput()
+	if err == nil {
+		return nil
+	}
+	errStr := utilfn.GetFirstLine(string(output))
+	errStr = strings.TrimPrefix(errStr, "bash: -c: ")
+	if len(errStr) == 0 {
+		return errors.New("bash syntax error")
+	}
+	return errors.New(errStr)
+}
+
 func (bashShellApi) ApplyShellStateDiff(oldState *packet.ShellState, diff *packet.ShellStateDiff) (*packet.ShellState, error) {
 	if oldState == nil {
 		return nil, fmt.Errorf("cannot apply diff, oldState is nil")
diff --git a/waveshell/pkg/shellapi/bashparser.go b/waveshell/pkg/shellapi/bashparser.go
index f56b33b37..889171ae4 100644
--- a/waveshell/pkg/shellapi/bashparser.go
+++ b/waveshell/pkg/shellapi/bashparser.go
@@ -214,9 +214,16 @@ func bashParseDeclareOutput(state *packet.ShellState, declareBytes []byte, pvarB
 				firstParseErr = err
 			}
 		}
-		if decl != nil && !BashNoStoreVarNames[decl.Name] {
-			declMap[decl.Name] = decl
+		if decl == nil {
+			continue
 		}
+		if BashNoStoreVarNames[decl.Name] {
+			continue
+		}
+		if strings.HasPrefix(decl.Name, "_wavetemp_") {
+			continue
+		}
+		declMap[decl.Name] = decl
 	}
 	pvarMap := parseExtVarOutput(pvarBytes, "", "")
 	utilfn.CombineMaps(declMap, pvarMap)
diff --git a/waveshell/pkg/shellapi/shellapi.go b/waveshell/pkg/shellapi/shellapi.go
index 81c481269..c948a56ee 100644
--- a/waveshell/pkg/shellapi/shellapi.go
+++ b/waveshell/pkg/shellapi/shellapi.go
@@ -28,6 +28,7 @@ import (
 )
 
 const GetVersionTimeout = 5 * time.Second
+const ValidateTimeout = 2 * time.Second
 const GetGitBranchCmdStr = `printf "GITBRANCH %s\x00" "$(git rev-parse --abbrev-ref HEAD 2>/dev/null)"`
 const GetK8sContextCmdStr = `printf "K8SCONTEXT %s\x00" "$(kubectl config current-context 2>/dev/null)"`
 const GetK8sNamespaceCmdStr = `printf "K8SNAMESPACE %s\x00" "$(kubectl config view --minify --output 'jsonpath={..namespace}' 2>/dev/null)"`
@@ -69,6 +70,7 @@ type ShellStateOutput struct {
 type ShellApi interface {
 	GetShellType() string
 	MakeExitTrap(fdNum int) (string, []byte)
+	ValidateCommandSyntax(cmdStr string) error
 	GetLocalMajorVersion() string
 	GetLocalShellPath() string
 	GetRemoteShellPath() string
diff --git a/waveshell/pkg/shellapi/zshapi.go b/waveshell/pkg/shellapi/zshapi.go
index 71cbdf4b4..461543c70 100644
--- a/waveshell/pkg/shellapi/zshapi.go
+++ b/waveshell/pkg/shellapi/zshapi.go
@@ -211,27 +211,41 @@ type ZshMap = map[ZshParamKey]string
 
 type zshShellApi struct{}
 
-func (z zshShellApi) GetShellType() string {
+func (zshShellApi) GetShellType() string {
 	return packet.ShellType_zsh
 }
 
-func (z zshShellApi) MakeExitTrap(fdNum int) (string, []byte) {
+func (zshShellApi) MakeExitTrap(fdNum int) (string, []byte) {
 	return MakeZshExitTrap(fdNum)
 }
 
-func (z zshShellApi) GetLocalMajorVersion() string {
+func (zshShellApi) GetLocalMajorVersion() string {
 	return GetLocalZshMajorVersion()
 }
 
-func (z zshShellApi) GetLocalShellPath() string {
+func (zshShellApi) GetLocalShellPath() string {
 	return "/bin/zsh"
 }
 
-func (z zshShellApi) GetRemoteShellPath() string {
+func (zshShellApi) GetRemoteShellPath() string {
 	return "zsh"
 }
 
-func (z zshShellApi) MakeRunCommand(cmdStr string, opts RunCommandOpts) string {
+func (zshShellApi) ValidateCommandSyntax(cmdStr string) error {
+	ctx, cancelFn := context.WithTimeout(context.Background(), ValidateTimeout)
+	defer cancelFn()
+	cmd := exec.CommandContext(ctx, GetLocalZshPath(), "-n", "-c", cmdStr)
+	output, err := cmd.CombinedOutput()
+	if err == nil {
+		return nil
+	}
+	if len(output) == 0 {
+		return errors.New("zsh syntax error")
+	}
+	return errors.New(utilfn.GetFirstLine(string(output)))
+}
+
+func (zshShellApi) MakeRunCommand(cmdStr string, opts RunCommandOpts) string {
 	if !opts.Sudo {
 		return cmdStr
 	}
@@ -242,7 +256,7 @@ func (z zshShellApi) MakeRunCommand(cmdStr string, opts RunCommandOpts) string {
 	}
 }
 
-func (z zshShellApi) MakeShExecCommand(cmdStr string, rcFileName string, usePty bool) *exec.Cmd {
+func (zshShellApi) MakeShExecCommand(cmdStr string, rcFileName string, usePty bool) *exec.Cmd {
 	return exec.Command(GetLocalZshPath(), "-l", "-i", "-c", cmdStr)
 }
 
@@ -274,7 +288,7 @@ func (z zshShellApi) GetShellState(ctx context.Context, outCh chan ShellStateOut
 	outCh <- ShellStateOutput{ShellState: rtn, Stats: stats}
 }
 
-func (z zshShellApi) GetBaseShellOpts() string {
+func (zshShellApi) GetBaseShellOpts() string {
 	return BaseZshOpts
 }
 
@@ -343,6 +357,9 @@ func (z zshShellApi) MakeRcFileStr(pk *packet.RunPacketType) string {
 		if strings.HasPrefix(varDecl.Name, "ZFTP_") {
 			continue
 		}
+		if strings.HasPrefix(varDecl.Name, "_wavetemp_") {
+			continue
+		}
 		if varDecl.IsExtVar {
 			continue
 		}
@@ -709,7 +726,7 @@ func makeZshFuncsStrForShellState(fnMap map[ZshParamKey]string) string {
 	return buf.String()
 }
 
-func (z zshShellApi) ParseShellStateOutput(outputBytes []byte) (*packet.ShellState, *packet.ShellStateStats, error) {
+func (zshShellApi) ParseShellStateOutput(outputBytes []byte) (*packet.ShellState, *packet.ShellStateStats, error) {
 	if scbase.IsDevMode() && DebugState {
 		writeStateToFile(packet.ShellType_zsh, outputBytes)
 	}
diff --git a/waveshell/pkg/shellapi/zshapi_test.go b/waveshell/pkg/shellapi/zshapi_test.go
index 557ac99ec..b5d1762e4 100644
--- a/waveshell/pkg/shellapi/zshapi_test.go
+++ b/waveshell/pkg/shellapi/zshapi_test.go
@@ -2,7 +2,9 @@ package shellapi
 
 import (
 	"fmt"
+	"log"
 	"testing"
+	"time"
 )
 
 func testSingleDecl(declStr string) {
@@ -45,3 +47,35 @@ func TestZshSafeDeclName(t *testing.T) {
 		t.Errorf("should not be safe")
 	}
 }
+
+func testValidate(t *testing.T, shell string, cmd string, expectErr bool) {
+	var sapi ShellApi
+	if shell == "bash" {
+		sapi = bashShellApi{}
+	} else if shell == "zsh" {
+		sapi = zshShellApi{}
+	} else {
+		t.Errorf("unknown shell %q", shell)
+		return
+	}
+	tstart := time.Now()
+	err := sapi.ValidateCommandSyntax(cmd)
+	log.Printf("shell:%s dur:%v err: %v\n", shell, time.Since(tstart), err)
+	if expectErr && err == nil {
+		t.Errorf("cmd %q, expected error", cmd)
+	}
+	if !expectErr && err != nil {
+		t.Errorf("cmd %q, unexpected error: %v", cmd, err)
+	}
+}
+
+func TestValidate(t *testing.T) {
+	testValidate(t, "zsh", "echo foo", false)
+	testValidate(t, "zsh", "foo >& &", true)
+	testValidate(t, "zsh", "cd .", false)
+	testValidate(t, "zsh", "echo foo | grep foo", false)
+	testValidate(t, "zsh", "x; echo \"hello", true)
+	testValidate(t, "bash", "echo foo", false)
+	testValidate(t, "bash", "foo >& &", true)
+	testValidate(t, "bash", "cd .; echo \"", true)
+}
diff --git a/waveshell/pkg/shexec/client.go b/waveshell/pkg/shexec/client.go
index 9efcf2250..04aea9b68 100644
--- a/waveshell/pkg/shexec/client.go
+++ b/waveshell/pkg/shexec/client.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/wavetermdev/waveterm/waveshell/pkg/base"
 	"github.com/wavetermdev/waveterm/waveshell/pkg/packet"
+	"github.com/wavetermdev/waveterm/waveshell/pkg/utilfn"
 	"golang.org/x/crypto/ssh"
 	"golang.org/x/mod/semver"
 )
@@ -274,7 +275,7 @@ func (cproc *ClientProc) ProxySingleOutput(ck base.CommandKey, sender *packet.Pa
 		cmdDuration := endTs.Sub(cproc.StartTs)
 		donePacket := packet.MakeCmdDonePacket(ck)
 		donePacket.Ts = endTs.UnixMilli()
-		donePacket.ExitCode = GetExitCode(exitErr)
+		donePacket.ExitCode = utilfn.GetExitCode(exitErr)
 		donePacket.DurationMs = int64(cmdDuration / time.Millisecond)
 		sender.SendPacket(donePacket)
 	}
diff --git a/waveshell/pkg/shexec/shexec.go b/waveshell/pkg/shexec/shexec.go
index 9ff6211da..7a5bdef51 100644
--- a/waveshell/pkg/shexec/shexec.go
+++ b/waveshell/pkg/shexec/shexec.go
@@ -31,6 +31,7 @@ import (
 	"github.com/wavetermdev/waveterm/waveshell/pkg/shellapi"
 	"github.com/wavetermdev/waveterm/waveshell/pkg/shellenv"
 	"github.com/wavetermdev/waveterm/waveshell/pkg/shellutil"
+	"github.com/wavetermdev/waveterm/waveshell/pkg/utilfn"
 	"github.com/wavetermdev/waveterm/waveshell/pkg/wlog"
 	"golang.org/x/mod/semver"
 	"golang.org/x/sys/unix"
@@ -826,6 +827,10 @@ func RunCommandSimple(pk *packet.RunPacketType, sender *packet.PacketSender, fro
 	var rtnStateWriter *os.File
 	rcFileStr := sapi.MakeRcFileStr(pk)
 	if pk.ReturnState {
+		err := sapi.ValidateCommandSyntax(pk.Command)
+		if err != nil {
+			return nil, err
+		}
 		pr, pw, err := os.Pipe()
 		if err != nil {
 			return nil, fmt.Errorf("cannot create returnstate pipe: %v", err)
@@ -894,7 +899,12 @@ func RunCommandSimple(pk *packet.RunPacketType, sender *packet.PacketSender, fro
 			os.Remove(cmd.TmpRcFileName)
 		}()
 	}
-	cmd.Cmd = sapi.MakeShExecCommand(pk.Command, rcFileName, pk.UsePty)
+	fullCmdStr := pk.Command
+	if pk.ReturnState {
+		// this ensures that the last command is a shell buitin so we always get our exit trap to run
+		fullCmdStr = fullCmdStr + "\nexit $? 2> /dev/null"
+	}
+	cmd.Cmd = sapi.MakeShExecCommand(fullCmdStr, rcFileName, pk.UsePty)
 	if !pk.StateComplete {
 		cmd.Cmd.Env = os.Environ()
 	}
@@ -1075,34 +1085,6 @@ func copyToCirFile(dest *cirfile.File, src io.Reader) error {
 	}
 }
 
-func GetCmdExitCode(cmd *exec.Cmd, err error) int {
-	if cmd == nil || cmd.ProcessState == nil {
-		return GetExitCode(err)
-	}
-	status, ok := cmd.ProcessState.Sys().(syscall.WaitStatus)
-	if !ok {
-		return cmd.ProcessState.ExitCode()
-	}
-	signaled := status.Signaled()
-	if signaled {
-		signal := status.Signal()
-		return 128 + int(signal)
-	}
-	exitStatus := status.ExitStatus()
-	return exitStatus
-}
-
-func GetExitCode(err error) int {
-	if err == nil {
-		return 0
-	}
-	if exitErr, ok := err.(*exec.ExitError); ok {
-		return exitErr.ExitCode()
-	} else {
-		return -1
-	}
-}
-
 func (c *ShExecType) ProcWait() error {
 	exitErr := c.Cmd.Wait()
 	c.Lock.Lock()
@@ -1139,7 +1121,7 @@ func (c *ShExecType) WaitForCommand() *packet.CmdDonePacketType {
 	endTs := time.Now()
 	cmdDuration := endTs.Sub(c.StartTs)
 	donePacket.Ts = endTs.UnixMilli()
-	donePacket.ExitCode = GetCmdExitCode(c.Cmd, exitErr)
+	donePacket.ExitCode = utilfn.GetCmdExitCode(c.Cmd, exitErr)
 	donePacket.DurationMs = int64(cmdDuration / time.Millisecond)
 	if c.FileNames != nil {
 		os.Remove(c.FileNames.StdinFifo) // best effort (no need to check error)
diff --git a/waveshell/pkg/utilfn/utilfn.go b/waveshell/pkg/utilfn/utilfn.go
index 608e36cc8..b9ef0e5c6 100644
--- a/waveshell/pkg/utilfn/utilfn.go
+++ b/waveshell/pkg/utilfn/utilfn.go
@@ -15,9 +15,11 @@ import (
 	mathrand "math/rand"
 	"net/http"
 	"os"
+	"os/exec"
 	"regexp"
 	"sort"
 	"strings"
+	"syscall"
 	"unicode/utf8"
 )
 
@@ -635,3 +637,39 @@ func DetectMimeType(path string) string {
 	}
 	return rtn
 }
+
+func GetCmdExitCode(cmd *exec.Cmd, err error) int {
+	if cmd == nil || cmd.ProcessState == nil {
+		return GetExitCode(err)
+	}
+	status, ok := cmd.ProcessState.Sys().(syscall.WaitStatus)
+	if !ok {
+		return cmd.ProcessState.ExitCode()
+	}
+	signaled := status.Signaled()
+	if signaled {
+		signal := status.Signal()
+		return 128 + int(signal)
+	}
+	exitStatus := status.ExitStatus()
+	return exitStatus
+}
+
+func GetExitCode(err error) int {
+	if err == nil {
+		return 0
+	}
+	if exitErr, ok := err.(*exec.ExitError); ok {
+		return exitErr.ExitCode()
+	} else {
+		return -1
+	}
+}
+
+func GetFirstLine(s string) string {
+	idx := strings.Index(s, "\n")
+	if idx == -1 {
+		return s
+	}
+	return s[0:idx]
+}
diff --git a/wavesrv/db/schema.sql b/wavesrv/db/schema.sql
index dcdfea604..d7225ff70 100644
--- a/wavesrv/db/schema.sql
+++ b/wavesrv/db/schema.sql
@@ -27,7 +27,7 @@ CREATE TABLE remote_instance (
     festate json NOT NULL,
     statebasehash varchar(36) NOT NULL,
     statediffhasharr json NOT NULL
-);
+, shelltype varchar(20) NOT NULL DEFAULT 'bash');
 CREATE TABLE state_base (
     basehash varchar(36) PRIMARY KEY,
     ts bigint NOT NULL,
@@ -55,10 +55,8 @@ CREATE TABLE remote (
     lastconnectts bigint NOT NULL,
     local boolean NOT NULL,
     archived boolean NOT NULL,
-    remoteidx int NOT NULL,
-    statevars json NOT NULL DEFAULT '{}',
-    sshconfigsrc varchar(36) NOT NULL DEFAULT 'waveterm-manual',
-    openaiopts json NOT NULL DEFAULT '{}');
+    remoteidx int NOT NULL
+, statevars json NOT NULL DEFAULT '{}', openaiopts json NOT NULL DEFAULT '{}', sshconfigsrc varchar(36) NOT NULL DEFAULT 'waveterm-manual', shellpref varchar(20) NOT NULL DEFAULT 'detect');
 CREATE TABLE history (
     historyid varchar(36) PRIMARY KEY,
     ts bigint NOT NULL,
@@ -203,7 +201,7 @@ CREATE TABLE IF NOT EXISTS "cmd" (
     rtnstate boolean NOT NULL,
     rtnbasehash varchar(36) NOT NULL,
     rtndiffhasharr json NOT NULL,
-    runout json NOT NULL,
+    runout json NOT NULL, restartts bigint NOT NULL DEFAULT 0,
     PRIMARY KEY (screenid, lineid)
 );
 CREATE TABLE cmd_migrate20 (
diff --git a/wavesrv/pkg/remote/remote.go b/wavesrv/pkg/remote/remote.go
index d01b7dc43..99de0f9b6 100644
--- a/wavesrv/pkg/remote/remote.go
+++ b/wavesrv/pkg/remote/remote.go
@@ -1735,7 +1735,7 @@ func (msh *MShellProc) Launch(interactive bool) {
 	msh.WriteToPtyBuffer("connected to %s\n", remoteCopy.RemoteCanonicalName)
 	go func() {
 		exitErr := cproc.Cmd.Wait()
-		exitCode := shexec.GetExitCode(exitErr)
+		exitCode := utilfn.GetExitCode(exitErr)
 		msh.WithLock(func() {
 			if msh.Status == StatusConnected || msh.Status == StatusConnecting {
 				msh.Status = StatusDisconnected