ghost: specify the proper shell to use

Author: aitjcize

overlord/sysutils_darwin.go

@@ -139,7 +139,7 @@ func Install() error {
 	<key>EnvironmentVariables</key>
 	<dict>
 		<key>SHELL</key>
-		<string>/bin/bash</string>
+		<string>%s</string>
 		<key>HOME</key>
 		<string>%s</string>
 		<key>TERM</key>
@@ -151,7 +151,7 @@ func Install() error {
 	<true/>
 </dict>
 </plist>
-`, argsXML, homeDir)
+`, argsXML, getUserShell(), homeDir)
 
 	launchAgentsDir := filepath.Join(homeDir, "Library", "LaunchAgents")
 	plistFilePath := filepath.Join(launchAgentsDir, "com.overlord.ghost.plist")

overlord/sysutils_linux.go

@@ -185,7 +185,7 @@ RequiresMountsFor=%s
 [Service]
 Type=simple
 User=%s
-Environment=SHELL=/bin/bash
+Environment=SHELL=%s
 Environment=HOME=%s
 Environment=TERM=xterm-256color
 ExecStart=%s %s
@@ -194,7 +194,7 @@ RestartSec=5
 
 [Install]
 WantedBy=multi-user.target
-`, homeDir, currentUser, homeDir, targetPath, cmdArgs)
+`, homeDir, currentUser, getUserShell(), homeDir, targetPath, cmdArgs)
 
 	serviceFilePath, err := getSystemdServicePath()
 	if err != nil {

overlord/utils.go

@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"os/exec"
 	"os/user"
 	"path/filepath"
 	"runtime"
@@ -152,6 +153,41 @@ func installBinaryToUserLocal() (string, error) {
 	return targetPath, nil
 }
 
+// getUserShell returns the user's current shell, with fallback to /bin/bash
+func getUserShell() string {
+	// Try to get shell from environment variable first
+	if shell := os.Getenv("SHELL"); shell != "" {
+		return shell
+	}
+
+	// Fallback: try to get from user database
+	if currentUser, err := user.Current(); err == nil {
+		// On Unix systems, we can try to parse /etc/passwd or use getent
+		if shell := getShellFromUserDB(currentUser.Username); shell != "" {
+			return shell
+		}
+	}
+
+	// Ultimate fallback
+	return "/bin/bash"
+}
+
+// getShellFromUserDB tries to get the user's shell from the user database
+func getShellFromUserDB(username string) string {
+	// Try using getent command (works on most Unix systems)
+	cmd := exec.Command("getent", "passwd", username)
+	output, err := cmd.Output()
+	if err == nil {
+		// Parse passwd entry: username:x:uid:gid:gecos:home:shell
+		fields := strings.Split(strings.TrimSpace(string(output)), ":")
+		if len(fields) >= 7 && fields[6] != "" {
+			return fields[6]
+		}
+	}
+
+	return ""
+}
+
 // getServiceCommand constructs the command line arguments for the service
 // by filtering out the --install flag from os.Args
 func getServiceCommand() []string {