Add --host file to restrict fetches

docs/router_backup.1

@@ -8,6 +8,7 @@ ipng-router-backup \- SSH Router Backup Tool
 .RI [ --password " PASSWORD" ]
 .RI [ --key-file " KEYFILE" ]
 .RI [ --port " PORT" ]
+.RI [ --host " HOSTNAME" ]...
 .SH DESCRIPTION
 .B router_backup
 is a tool for backing up router configurations via SSH. It connects to multiple routers defined in a YAML configuration file and executes commands, saving the output to files.
@@ -30,6 +31,9 @@ SSH private key file path
 .BR --port " \fIPORT\fR"
 SSH port number (default: 22)
 .TP
+.BR --host " \fIHOSTNAME\fR"
+Specific host(s) to process (can be repeated, processes all if not specified)
+.TP
 .BR --help
 Show help message
 .SH CONFIGURATION
@@ -81,6 +85,11 @@ Using password authentication:
 .EX
 ipng-router-backup --config config.yaml --password mysecretpass
 .EE
+.TP
+Process specific hosts only:
+.EX
+ipng-router-backup --config config.yaml --host asw100 --host asw120
+.EE
 .SH FILES
 .TP
 .I /etc/ipng-router-backup/config.yaml.example

src/router_backup.go

@@ -221,6 +221,7 @@ func main() {
 	var keyFile string
 	var port int
 	var outputDir string
+	var hostFilter []string
 
 	var rootCmd = &cobra.Command{
 		Use:   "ipng-router-backup",
@@ -250,10 +251,23 @@ func main() {
 				log.Fatal("No devices found in config file")
 			}
 
-			successCount := 0
-			totalCount := len(config.Devices)
+			// Filter devices if --host flags are provided
+			devicesToProcess := config.Devices
+			if len(hostFilter) > 0 {
+				devicesToProcess = make(map[string]Device)
+				for _, hostname := range hostFilter {
+					if deviceConfig, exists := config.Devices[hostname]; exists {
+						devicesToProcess[hostname] = deviceConfig
+					} else {
+						fmt.Printf("Warning: Host '%s' not found in config file\n", hostname)
+					}
+				}
+			}
 
-			for hostname, deviceConfig := range config.Devices {
+			successCount := 0
+			totalCount := len(devicesToProcess)
+
+			for hostname, deviceConfig := range devicesToProcess {
 				fmt.Printf("\nProcessing device: %s (type: %s)\n", hostname, deviceConfig.Type)
 
 				user := deviceConfig.User
@@ -306,6 +320,7 @@ func main() {
 	rootCmd.Flags().StringVar(&keyFile, "key-file", "", "SSH private key file path")
 	rootCmd.Flags().IntVar(&port, "port", 22, "SSH port")
 	rootCmd.Flags().StringVar(&outputDir, "output-dir", "/tmp", "Output directory for command output files")
+	rootCmd.Flags().StringSliceVar(&hostFilter, "host", []string{}, "Specific host(s) to process (can be repeated, processes all if not specified)")
 
 	rootCmd.MarkFlagRequired("config")