all or some

main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"flag"
+	"strings"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -12,7 +14,33 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+type stringSlice []string
+
+func (s *stringSlice) String() string {
+	return strings.Join(*s, ",")
+}
+
+func (s *stringSlice) Set(value string) error {
+	*s = append(*s, value)
+	return nil
+}
+
+
 func main() {
+	
+	var interfaces stringSlice
+	flag.Var(&interfaces, "iface", "Interface(s) to filter on (can be specified multiple times)")
+	flag.Parse()
+	
+	// Build lookup map
+	filterSet := make(map[string]struct{})
+	for _, name := range interfaces {
+		filterSet[name] = struct{}{}
+	}
+	
+	// Determine if we are filtering at all
+	filtering := len(filterSet) > 0
+
 	headerStyle := lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("63"))
 	ipStyle := lipgloss.NewStyle().Foreground(lipgloss.Color("203"))
 	upStyle := lipgloss.NewStyle().Foreground(lipgloss.Color("42"))
@@ -33,12 +61,18 @@ func main() {
 		return
 	}
 	
+
 	for _, link := range links {
 		attrs := link.Attrs()
 		if attrs == nil {
 			continue
 		}
 
+		if filtering {
+			if _, ok := filterSet[attrs.Name]; !ok {
+				continue
+			}
+		}
 		state := downStyle.Render("DOWN")
 		if attrs.Flags&net.FlagUp != 0 {
 			state = upStyle.Render("UP")