build: add aur target

.github/workflows/release.yaml

@@ -9,7 +9,7 @@ permissions:
   contents: write
 
 jobs:
-  goreleaser:
+  release-linux:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
@@ -20,11 +20,31 @@ jobs:
         with:
           go-version: "1.25.0"
 
-      - name: run goreleaser
+      - name: release linux
         uses: goreleaser/goreleaser-action@v6
         with:
           version: "~> v2"
           args: release --clean
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          AUR_KEY: ${{ secrets.AUR_KEY }}
 
+  release-darwin:
+    needs: release-linux
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: actions/setup-go@v6
+        with:
+          go-version: "1.25.0"
+
+      - name: release darwin
+        uses: goreleaser/goreleaser-action@v6
+        with:
+          version: "~> v2"
+          args: release --clean --config .goreleaser-darwin.yaml --skip=validate
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -27,6 +27,9 @@ Thumbs.db
 # go
 vendor/
 
+# nix
+result
+
 # misc
 *.log
 *.tmp

.goreleaser-darwin.yaml

@@ -0,0 +1,39 @@
+version: 2
+
+project_name: snitch
+
+builds:
+  - id: darwin
+    env:
+      - CGO_ENABLED=1
+    goos:
+      - darwin
+    goarch:
+      - amd64
+      - arm64
+    ldflags:
+      - -s -w
+      - -X snitch/cmd.Version={{.Version}}
+      - -X snitch/cmd.Commit={{.ShortCommit}}
+      - -X snitch/cmd.Date={{.Date}}
+
+archives:
+  - formats:
+      - tar.gz
+    name_template: >-
+      {{ .ProjectName }}_
+      {{- .Version }}_
+      {{- .Os }}_
+      {{- .Arch }}
+    files:
+      - LICENSE
+      - README.md
+
+release:
+  github:
+    owner: karol-broda
+    name: snitch
+  draft: false
+  prerelease: auto
+  mode: append
+

.goreleaser.yaml

@@ -7,7 +7,8 @@ before:
     - go mod tidy
 
 builds:
-  - env:
+  - id: linux
+    env:
       - CGO_ENABLED=0
     goos:
       - linux
@@ -32,6 +33,9 @@ archives:
       {{- .Os }}_
       {{- .Arch }}
       {{- if .Arm }}v{{ .Arm }}{{ end }}
+    files:
+      - LICENSE
+      - README.md
 
 checksum:
   name_template: "checksums.txt"
@@ -60,10 +64,30 @@ nfpms:
       - rpm
       - apk
 
+aurs:
+  - name: snitch-bin
+    homepage: https://github.com/karol-broda/snitch
+    description: a friendlier ss/netstat for humans
+    maintainers:
+      - "Karol Broda <me@karolbroda.com>"
+    license: MIT
+    private_key: "{{ .Env.AUR_KEY }}"
+    git_url: "ssh://aur@aur.archlinux.org/snitch-bin.git"
+    depends:
+      - glibc
+    provides:
+      - snitch
+    conflicts:
+      - snitch
+    package: |-
+      install -Dm755 "./snitch" "${pkgdir}/usr/bin/snitch"
+      install -Dm644 "./LICENSE" "${pkgdir}/usr/share/licenses/snitch/LICENSE"
+    commit_msg_template: "Update to {{ .Tag }}"
+    skip_upload: auto
+
 release:
   github:
     owner: karol-broda
     name: snitch
   draft: false
   prerelease: auto
-

Makefile

@@ -0,0 +1,23 @@
+.PHONY: build test lint demo demo-build demo-run clean
+
+build:
+	go build -o snitch .
+
+test:
+	go test ./...
+
+lint:
+	golangci-lint run
+
+demo: demo-build demo-run
+
+demo-build:
+	docker build -f demo/Dockerfile -t snitch-demo .
+
+demo-run:
+	docker run --rm -v $(PWD)/demo:/output snitch-demo
+
+clean:
+	rm -f snitch
+	rm -f demo/demo.gif
+

README.md

@@ -2,12 +2,59 @@
 
 a friendlier `ss` / `netstat` for humans. inspect network connections with a clean tui or styled tables.
 
+![snitch demo](demo/demo.gif)
+
 ## install
 
+### go
+
 ```bash
 go install github.com/karol-broda/snitch@latest
 ```
 
+### nixos / nix
+
+```bash
+# try it
+nix run github:karol-broda/snitch
+
+# install to profile
+nix profile install github:karol-broda/snitch
+
+# or add to flake inputs
+{
+  inputs.snitch.url = "github:karol-broda/snitch";
+}
+# then use: inputs.snitch.packages.${system}.default
+```
+
+### arch linux (aur)
+
+```bash
+# with yay
+yay -S snitch-bin
+
+# with paru
+paru -S snitch-bin
+```
+
+### binary
+
+download from [releases](https://github.com/karol-broda/snitch/releases):
+
+- **linux:** `snitch_<version>_linux_<arch>.tar.gz` or `.deb`/`.rpm`/`.apk`
+- **macos:** `snitch_<version>_darwin_<arch>.tar.gz`
+
+```bash
+tar xzf snitch_*.tar.gz
+sudo mv snitch /usr/local/bin/
+```
+
+> **macos:** if blocked with "cannot be opened because the developer cannot be verified", run:
+> ```bash
+> xattr -d com.apple.quarantine /usr/local/bin/snitch
+> ```
+
 ## quick start
 
 ```bash
@@ -41,6 +88,9 @@ g/G           top/bottom
 t/u           toggle tcp/udp
 l/e/o         toggle listen/established/other
 s/S           cycle sort / reverse
+w             watch/monitor process (highlight)
+W             clear all watched
+K             kill process (with confirmation)
 /             search
 enter         connection details
 ?             help
@@ -139,5 +189,6 @@ theme = "auto"
 
 ## requirements
 
-- linux (reads from `/proc/net/*`)
+- linux or macos
-- root or `CAP_NET_ADMIN` for full process info
+- linux: reads from `/proc/net/*`, root or `CAP_NET_ADMIN` for full process info
+- macos: uses system APIs, may require sudo for full process info

cmd/cli_test.go

@@ -361,8 +361,8 @@ func resetGlobalFlags() {
 	showTimestamp = false
 	sortBy = ""
 	fields = ""
-	ipv4 = false
+	filterIPv4 = false
-	ipv6 = false
+	filterIPv6 = false
 	colorMode = "auto"
 	numeric = false
 }

cmd/ls.go

@@ -22,20 +22,15 @@ import (
 	"golang.org/x/term"
 )
 
+// ls-specific flags
 var (
 	outputFormat  string
 	noHeaders     bool
 	showTimestamp bool
 	sortBy        string
 	fields        string
-	ipv4          bool
-	ipv6          bool
 	colorMode     string
 	numeric       bool
-	lsTCP         bool
-	lsUDP         bool
-	lsListen      bool
-	lsEstab       bool
 	plainOutput   bool
 )
 
@@ -56,39 +51,16 @@ Available filters:
 }
 
 func runListCommand(outputFormat string, args []string) {
-	color.Init(colorMode)
+	rt, err := NewRuntime(args, colorMode, numeric)
-
-	filters, err := parseFilters(args)
-	if err != nil {
-		log.Fatalf("Error parsing filters: %v", err)
-	}
-	filters.IPv4 = ipv4
-	filters.IPv6 = ipv6
-
-	// apply shortcut flags
-	if lsTCP && !lsUDP {
-		filters.Proto = "tcp"
-	} else if lsUDP && !lsTCP {
-		filters.Proto = "udp"
-	}
-	if lsListen && !lsEstab {
-		filters.State = "LISTEN"
-	} else if lsEstab && !lsListen {
-		filters.State = "ESTABLISHED"
-	}
-
-	connections, err := collector.GetConnections()
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	filteredConnections := collector.FilterConnections(connections, filters)
+	// apply sorting
-
 	if sortBy != "" {
-		collector.SortConnections(filteredConnections, collector.ParseSortOptions(sortBy))
+		rt.SortConnections(collector.ParseSortOptions(sortBy))
 	} else {
-		// default sort by local port
+		rt.SortConnections(collector.SortOptions{
-		collector.SortConnections(filteredConnections, collector.SortOptions{
 			Field:     collector.SortByLport,
 			Direction: collector.SortAsc,
 		})
@@ -99,93 +71,26 @@ func runListCommand(outputFormat string, args []string) {
 		selectedFields = strings.Split(fields, ",")
 	}
 
-	switch outputFormat {
+	renderList(rt.Connections, outputFormat, selectedFields)
+}
+
+func renderList(connections []collector.Connection, format string, selectedFields []string) {
+	switch format {
 	case "json":
-		printJSON(filteredConnections)
+		printJSON(connections)
 	case "csv":
-		printCSV(filteredConnections, !noHeaders, showTimestamp, selectedFields)
+		printCSV(connections, !noHeaders, showTimestamp, selectedFields)
 	case "table", "wide":
 		if plainOutput {
-			printPlainTable(filteredConnections, !noHeaders, showTimestamp, selectedFields)
+			printPlainTable(connections, !noHeaders, showTimestamp, selectedFields)
 		} else {
-			printStyledTable(filteredConnections, !noHeaders, selectedFields)
+			printStyledTable(connections, !noHeaders, selectedFields)
 		}
 	default:
-		log.Fatalf("Invalid output format: %s. Valid formats are: table, wide, json, csv", outputFormat)
+		log.Fatalf("Invalid output format: %s. Valid formats are: table, wide, json, csv", format)
 	}
 }
 
-func parseFilters(args []string) (collector.FilterOptions, error) {
-	filters := collector.FilterOptions{}
-	for _, arg := range args {
-		parts := strings.SplitN(arg, "=", 2)
-		if len(parts) != 2 {
-			return filters, fmt.Errorf("invalid filter format: %s", arg)
-		}
-		key, value := parts[0], parts[1]
-		switch strings.ToLower(key) {
-		case "proto":
-			filters.Proto = value
-		case "state":
-			filters.State = value
-		case "pid":
-			pid, err := strconv.Atoi(value)
-			if err != nil {
-				return filters, fmt.Errorf("invalid pid value: %s", value)
-			}
-			filters.Pid = pid
-		case "proc":
-			filters.Proc = value
-		case "lport":
-			port, err := strconv.Atoi(value)
-			if err != nil {
-				return filters, fmt.Errorf("invalid lport value: %s", value)
-			}
-			filters.Lport = port
-		case "rport":
-			port, err := strconv.Atoi(value)
-			if err != nil {
-				return filters, fmt.Errorf("invalid rport value: %s", value)
-			}
-			filters.Rport = port
-		case "user":
-			uid, err := strconv.Atoi(value)
-			if err == nil {
-				filters.UID = uid
-			} else {
-				filters.User = value
-			}
-		case "laddr":
-			filters.Laddr = value
-		case "raddr":
-			filters.Raddr = value
-		case "contains":
-			filters.Contains = value
-		case "if", "interface":
-			filters.Interface = value
-		case "mark":
-			filters.Mark = value
-		case "namespace":
-			filters.Namespace = value
-		case "inode":
-			inode, err := strconv.ParseInt(value, 10, 64)
-			if err != nil {
-				return filters, fmt.Errorf("invalid inode value: %s", value)
-			}
-			filters.Inode = inode
-		case "since":
-			since, sinceRel, err := collector.ParseTimeFilter(value)
-			if err != nil {
-				return filters, fmt.Errorf("invalid since value: %s", value)
-			}
-			filters.Since = since
-			filters.SinceRel = sinceRel
-		default:
-			return filters, fmt.Errorf("unknown filter key: %s", key)
-		}
-	}
-	return filters, nil
-}
 
 func getFieldMap(c collector.Connection) map[string]string {
 	laddr := c.Laddr
@@ -483,20 +388,16 @@ func init() {
 
 	cfg := config.Get()
 
+	// ls-specific flags
 	lsCmd.Flags().StringVarP(&outputFormat, "output", "o", cfg.Defaults.OutputFormat, "Output format (table, wide, json, csv)")
 	lsCmd.Flags().BoolVar(&noHeaders, "no-headers", cfg.Defaults.NoHeaders, "Omit headers for table/csv output")
 	lsCmd.Flags().BoolVar(&showTimestamp, "ts", false, "Include timestamp in output")
 	lsCmd.Flags().StringVarP(&sortBy, "sort", "s", cfg.Defaults.SortBy, "Sort by column (e.g., pid:desc)")
 	lsCmd.Flags().StringVarP(&fields, "fields", "f", strings.Join(cfg.Defaults.Fields, ","), "Comma-separated list of fields to show")
-	lsCmd.Flags().BoolVarP(&ipv4, "ipv4", "4", cfg.Defaults.IPv4, "Only show IPv4 connections")
-	lsCmd.Flags().BoolVarP(&ipv6, "ipv6", "6", cfg.Defaults.IPv6, "Only show IPv6 connections")
 	lsCmd.Flags().StringVar(&colorMode, "color", cfg.Defaults.Color, "Color mode (auto, always, never)")
 	lsCmd.Flags().BoolVarP(&numeric, "numeric", "n", cfg.Defaults.Numeric, "Don't resolve hostnames")
-
-	// shortcut filters
-	lsCmd.Flags().BoolVarP(&lsTCP, "tcp", "t", false, "Show only TCP connections")
-	lsCmd.Flags().BoolVarP(&lsUDP, "udp", "u", false, "Show only UDP connections")
-	lsCmd.Flags().BoolVarP(&lsListen, "listen", "l", false, "Show only listening sockets")
-	lsCmd.Flags().BoolVarP(&lsEstab, "established", "e", false, "Show only established connections")
 	lsCmd.Flags().BoolVarP(&plainOutput, "plain", "p", false, "Plain output (parsable, no styling)")
+
+	// shared filter flags
+	addFilterFlags(lsCmd)
 }

cmd/ls_test.go

@@ -251,7 +251,7 @@ func TestParseFilters(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			filters, err := parseFilters(tt.args)
+			filters, err := ParseFilterArgs(tt.args)
 
 			if tt.expectError {
 				if err == nil {

cmd/root.go

@@ -40,12 +40,11 @@ func init() {
 	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.config/snitch/snitch.toml)")
 	rootCmd.PersistentFlags().Bool("debug", false, "enable debug logs to stderr")
 
-	// add top's filter flags to root so `snitch -l` works
+	// add top's flags to root so `snitch -l` works (defaults to top command)
 	cfg := config.Get()
 	rootCmd.Flags().StringVar(&topTheme, "theme", cfg.Defaults.Theme, "Theme for TUI (dark, light, mono, auto)")
 	rootCmd.Flags().DurationVarP(&topInterval, "interval", "i", 0, "Refresh interval (default 1s)")
-	rootCmd.Flags().BoolVarP(&topTCP, "tcp", "t", false, "Show only TCP connections")
+
-	rootCmd.Flags().BoolVarP(&topUDP, "udp", "u", false, "Show only UDP connections")
+	// shared filter flags for root command
-	rootCmd.Flags().BoolVarP(&topListen, "listen", "l", false, "Show only listening sockets")
+	addFilterFlags(rootCmd)
-	rootCmd.Flags().BoolVarP(&topEstab, "established", "e", false, "Show only established connections")
 }

cmd/runtime.go

@@ -0,0 +1,201 @@
+package cmd
+
+import (
+	"fmt"
+	"snitch/internal/collector"
+	"snitch/internal/color"
+	"strconv"
+	"strings"
+
+	"github.com/spf13/cobra"
+)
+
+// Runtime holds the shared state for all commands.
+// it handles common filter logic, fetching, and filtering connections.
+type Runtime struct {
+	// filter options built from flags and args
+	Filters collector.FilterOptions
+
+	// filtered connections ready for rendering
+	Connections []collector.Connection
+
+	// common settings
+	ColorMode string
+	Numeric   bool
+}
+
+// shared filter flags - used by all commands
+var (
+	filterTCP    bool
+	filterUDP    bool
+	filterListen bool
+	filterEstab  bool
+	filterIPv4   bool
+	filterIPv6   bool
+)
+
+// BuildFilters constructs FilterOptions from command args and shortcut flags.
+func BuildFilters(args []string) (collector.FilterOptions, error) {
+	filters, err := ParseFilterArgs(args)
+	if err != nil {
+		return filters, err
+	}
+
+	// apply ipv4/ipv6 flags
+	filters.IPv4 = filterIPv4
+	filters.IPv6 = filterIPv6
+
+	// apply protocol shortcut flags
+	if filterTCP && !filterUDP {
+		filters.Proto = "tcp"
+	} else if filterUDP && !filterTCP {
+		filters.Proto = "udp"
+	}
+
+	// apply state shortcut flags
+	if filterListen && !filterEstab {
+		filters.State = "LISTEN"
+	} else if filterEstab && !filterListen {
+		filters.State = "ESTABLISHED"
+	}
+
+	return filters, nil
+}
+
+// FetchConnections gets connections from the collector and applies filters.
+func FetchConnections(filters collector.FilterOptions) ([]collector.Connection, error) {
+	connections, err := collector.GetConnections()
+	if err != nil {
+		return nil, err
+	}
+
+	return collector.FilterConnections(connections, filters), nil
+}
+
+// NewRuntime creates a runtime with fetched and filtered connections.
+func NewRuntime(args []string, colorMode string, numeric bool) (*Runtime, error) {
+	color.Init(colorMode)
+
+	filters, err := BuildFilters(args)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse filters: %w", err)
+	}
+
+	connections, err := FetchConnections(filters)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch connections: %w", err)
+	}
+
+	return &Runtime{
+		Filters:     filters,
+		Connections: connections,
+		ColorMode:   colorMode,
+		Numeric:     numeric,
+	}, nil
+}
+
+// SortConnections sorts the runtime's connections in place.
+func (r *Runtime) SortConnections(opts collector.SortOptions) {
+	collector.SortConnections(r.Connections, opts)
+}
+
+// ParseFilterArgs parses key=value filter arguments.
+// exported for testing.
+func ParseFilterArgs(args []string) (collector.FilterOptions, error) {
+	filters := collector.FilterOptions{}
+	for _, arg := range args {
+		parts := strings.SplitN(arg, "=", 2)
+		if len(parts) != 2 {
+			return filters, fmt.Errorf("invalid filter format: %s (expected key=value)", arg)
+		}
+		key, value := parts[0], parts[1]
+		if err := applyFilter(&filters, key, value); err != nil {
+			return filters, err
+		}
+	}
+	return filters, nil
+}
+
+// applyFilter applies a single key=value filter to FilterOptions.
+func applyFilter(filters *collector.FilterOptions, key, value string) error {
+	switch strings.ToLower(key) {
+	case "proto":
+		filters.Proto = value
+	case "state":
+		filters.State = value
+	case "pid":
+		pid, err := strconv.Atoi(value)
+		if err != nil {
+			return fmt.Errorf("invalid pid value: %s", value)
+		}
+		filters.Pid = pid
+	case "proc":
+		filters.Proc = value
+	case "lport":
+		port, err := strconv.Atoi(value)
+		if err != nil {
+			return fmt.Errorf("invalid lport value: %s", value)
+		}
+		filters.Lport = port
+	case "rport":
+		port, err := strconv.Atoi(value)
+		if err != nil {
+			return fmt.Errorf("invalid rport value: %s", value)
+		}
+		filters.Rport = port
+	case "user":
+		uid, err := strconv.Atoi(value)
+		if err == nil {
+			filters.UID = uid
+		} else {
+			filters.User = value
+		}
+	case "laddr":
+		filters.Laddr = value
+	case "raddr":
+		filters.Raddr = value
+	case "contains":
+		filters.Contains = value
+	case "if", "interface":
+		filters.Interface = value
+	case "mark":
+		filters.Mark = value
+	case "namespace":
+		filters.Namespace = value
+	case "inode":
+		inode, err := strconv.ParseInt(value, 10, 64)
+		if err != nil {
+			return fmt.Errorf("invalid inode value: %s", value)
+		}
+		filters.Inode = inode
+	case "since":
+		since, sinceRel, err := collector.ParseTimeFilter(value)
+		if err != nil {
+			return fmt.Errorf("invalid since value: %s", value)
+		}
+		filters.Since = since
+		filters.SinceRel = sinceRel
+	default:
+		return fmt.Errorf("unknown filter key: %s", key)
+	}
+	return nil
+}
+
+// FilterFlagsHelp returns the help text for common filter flags.
+const FilterFlagsHelp = `
+Filters are specified in key=value format. For example:
+  snitch ls proto=tcp state=established
+
+Available filters:
+  proto, state, pid, proc, lport, rport, user, laddr, raddr, contains, if, mark, namespace, inode, since`
+
+// addFilterFlags adds the common filter flags to a command.
+func addFilterFlags(cmd *cobra.Command) {
+	cmd.Flags().BoolVarP(&filterTCP, "tcp", "t", false, "Show only TCP connections")
+	cmd.Flags().BoolVarP(&filterUDP, "udp", "u", false, "Show only UDP connections")
+	cmd.Flags().BoolVarP(&filterListen, "listen", "l", false, "Show only listening sockets")
+	cmd.Flags().BoolVarP(&filterEstab, "established", "e", false, "Show only established connections")
+	cmd.Flags().BoolVarP(&filterIPv4, "ipv4", "4", false, "Only show IPv4 connections")
+	cmd.Flags().BoolVarP(&filterIPv6, "ipv6", "6", false, "Only show IPv6 connections")
+}
+

cmd/stats.go

@@ -39,6 +39,7 @@ type InterfaceStats struct {
 	Count     int    `json:"count"`
 }
 
+// stats-specific flags
 var (
 	statsOutputFormat string
 	statsInterval     time.Duration
@@ -63,12 +64,10 @@ Available filters:
 }
 
 func runStatsCommand(args []string) {
-	filters, err := parseFilters(args)
+	filters, err := BuildFilters(args)
 	if err != nil {
 		log.Fatalf("Error parsing filters: %v", err)
 	}
-	filters.IPv4 = ipv4
-	filters.IPv6 = ipv6
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
@@ -121,13 +120,11 @@ func runStatsCommand(args []string) {
 }
 
 func generateStats(filters collector.FilterOptions) (*StatsData, error) {
-	connections, err := collector.GetConnections()
+	filteredConnections, err := FetchConnections(filters)
 	if err != nil {
 		return nil, err
 	}
 
-	filteredConnections := collector.FilterConnections(connections, filters)
-
 	stats := &StatsData{
 		Timestamp: time.Now(),
 		Total:     len(filteredConnections),
@@ -291,10 +288,13 @@ func printStatsTable(stats *StatsData, headers bool) {
 
 func init() {
 	rootCmd.AddCommand(statsCmd)
+
+	// stats-specific flags
 	statsCmd.Flags().StringVarP(&statsOutputFormat, "output", "o", "table", "Output format (table, json, csv)")
 	statsCmd.Flags().DurationVarP(&statsInterval, "interval", "i", 0, "Refresh interval (0 = one-shot)")
 	statsCmd.Flags().IntVarP(&statsCount, "count", "c", 0, "Number of iterations (0 = unlimited)")
 	statsCmd.Flags().BoolVar(&statsNoHeaders, "no-headers", false, "Omit headers for table/csv output")
-	statsCmd.Flags().BoolVarP(&ipv4, "ipv4", "4", false, "Only show IPv4 connections")
+
-	statsCmd.Flags().BoolVarP(&ipv6, "ipv6", "6", false, "Only show IPv6 connections")
+	// shared filter flags
+	addFilterFlags(statsCmd)
 }

cmd/testdata/golden/mixed_protocols_json.golden

@@ -28,7 +28,7 @@
     "uid": 0,
     "proto": "udp",
     "ipversion": "",
-    "state": "CONNECTED",
+    "state": "LISTEN",
     "laddr": "0.0.0.0",
     "lport": 53,
     "raddr": "",

cmd/testdata/golden/mixed_protocols_table.golden

@@ -1,4 +1,4 @@
 PID   PROCESS      USER   PROTO           STATE                LADDR            LPORT    RADDR   RPORT
 1            tcp-server          tcp    LISTEN      0.0.0.0          http             0
-2            udp-server          udp    CONNECTED   0.0.0.0          domain           0
+2            udp-server          udp    LISTEN      0.0.0.0          domain           0
 3            unix-app            unix   CONNECTED   /tmp/test.sock   0                0

cmd/testdata/golden/udp_filter_json.golden

@@ -7,7 +7,7 @@
     "uid": 0,
     "proto": "udp",
     "ipversion": "",
-    "state": "CONNECTED",
+    "state": "LISTEN",
     "laddr": "0.0.0.0",
     "lport": 53,
     "raddr": "",

cmd/top.go

@@ -10,13 +10,10 @@ import (
 	"github.com/spf13/cobra"
 )
 
+// top-specific flags
 var (
 	topTheme    string
 	topInterval time.Duration
-	topTCP      bool
-	topUDP      bool
-	topListen   bool
-	topEstab    bool
 )
 
 var topCmd = &cobra.Command{
@@ -36,11 +33,11 @@ var topCmd = &cobra.Command{
 		}
 
 		// if any filter flag is set, use exclusive mode
-		if topTCP || topUDP || topListen || topEstab {
+		if filterTCP || filterUDP || filterListen || filterEstab {
-			opts.TCP = topTCP
+			opts.TCP = filterTCP
-			opts.UDP = topUDP
+			opts.UDP = filterUDP
-			opts.Listening = topListen
+			opts.Listening = filterListen
-			opts.Established = topEstab
+			opts.Established = filterEstab
 			opts.Other = false
 			opts.FilterSet = true
 		}
@@ -57,10 +54,11 @@ var topCmd = &cobra.Command{
 func init() {
 	rootCmd.AddCommand(topCmd)
 	cfg := config.Get()
+
+	// top-specific flags
 	topCmd.Flags().StringVar(&topTheme, "theme", cfg.Defaults.Theme, "Theme for TUI (dark, light, mono, auto)")
 	topCmd.Flags().DurationVarP(&topInterval, "interval", "i", time.Second, "Refresh interval")
-	topCmd.Flags().BoolVarP(&topTCP, "tcp", "t", false, "Show only TCP connections")
+
-	topCmd.Flags().BoolVarP(&topUDP, "udp", "u", false, "Show only UDP connections")
+	// shared filter flags
-	topCmd.Flags().BoolVarP(&topListen, "listen", "l", false, "Show only listening sockets")
+	addFilterFlags(topCmd)
-	topCmd.Flags().BoolVarP(&topEstab, "established", "e", false, "Show only established connections")
 }

cmd/trace.go

@@ -47,12 +47,10 @@ Available filters:
 }
 
 func runTraceCommand(args []string) {
-	filters, err := parseFilters(args)
+	filters, err := BuildFilters(args)
 	if err != nil {
 		log.Fatalf("Error parsing filters: %v", err)
 	}
-	filters.IPv4 = ipv4
-	filters.IPv6 = ipv6
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
@@ -222,11 +220,14 @@ func printTraceEventHuman(event TraceEvent) {
 
 func init() {
 	rootCmd.AddCommand(traceCmd)
+
+	// trace-specific flags
 	traceCmd.Flags().DurationVarP(&traceInterval, "interval", "i", time.Second, "Polling interval (e.g., 500ms, 2s)")
 	traceCmd.Flags().IntVarP(&traceCount, "count", "c", 0, "Number of events to capture (0 = unlimited)")
 	traceCmd.Flags().StringVarP(&traceOutputFormat, "output", "o", "human", "Output format (human, json)")
 	traceCmd.Flags().BoolVarP(&traceNumeric, "numeric", "n", false, "Don't resolve hostnames")
 	traceCmd.Flags().BoolVar(&traceTimestamp, "ts", false, "Include timestamp in output")
-	traceCmd.Flags().BoolVarP(&ipv4, "ipv4", "4", false, "Only trace IPv4 connections")
+
-	traceCmd.Flags().BoolVarP(&ipv6, "ipv6", "6", false, "Only trace IPv6 connections")
+	// shared filter flags
+	addFilterFlags(traceCmd)
 }

cmd/watch.go

@@ -7,7 +7,6 @@ import (
 	"log"
 	"os"
 	"os/signal"
-	"snitch/internal/collector"
 	"syscall"
 	"time"
 
@@ -36,17 +35,14 @@ Available filters:
 }
 
 func runWatchCommand(args []string) {
-	filters, err := parseFilters(args)
+	filters, err := BuildFilters(args)
 	if err != nil {
 		log.Fatalf("Error parsing filters: %v", err)
 	}
-	filters.IPv4 = ipv4
-	filters.IPv6 = ipv6
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	// Handle interrupts gracefully
 	sigChan := make(chan os.Signal, 1)
 	signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM)
 	go func() {
@@ -63,18 +59,16 @@ func runWatchCommand(args []string) {
 		case <-ctx.Done():
 			return
 		case <-ticker.C:
-			connections, err := collector.GetConnections()
+			connections, err := FetchConnections(filters)
 			if err != nil {
 				log.Printf("Error getting connections: %v", err)
 				continue
 			}
 
-			filteredConnections := collector.FilterConnections(connections, filters)
-			
 			frame := map[string]interface{}{
 				"timestamp":   time.Now().Format(time.RFC3339Nano),
-				"connections": filteredConnections,
+				"connections": connections,
-				"count":       len(filteredConnections),
+				"count":       len(connections),
 			}
 
 			jsonOutput, err := json.Marshal(frame)
@@ -95,8 +89,11 @@ func runWatchCommand(args []string) {
 
 func init() {
 	rootCmd.AddCommand(watchCmd)
+
+	// watch-specific flags
 	watchCmd.Flags().DurationVarP(&watchInterval, "interval", "i", time.Second, "Refresh interval (e.g., 500ms, 2s)")
 	watchCmd.Flags().IntVarP(&watchCount, "count", "c", 0, "Number of frames to emit (0 = unlimited)")
-	watchCmd.Flags().BoolVarP(&ipv4, "ipv4", "4", false, "Only show IPv4 connections")
+
-	watchCmd.Flags().BoolVarP(&ipv6, "ipv6", "6", false, "Only show IPv6 connections")
+	// shared filter flags
+	addFilterFlags(watchCmd)
 }

demo/Dockerfile

@@ -0,0 +1,36 @@
+# syntax=docker/dockerfile:1
+
+# build stage - compile snitch
+FROM golang:1.25.0-bookworm AS builder
+WORKDIR /src
+COPY . .
+RUN --mount=type=cache,target=/go/pkg/mod \
+    --mount=type=cache,target=/root/.cache/go-build \
+    go build -o snitch .
+
+# runtime stage - official vhs image has ffmpeg, chromium, ttyd pre-installed
+FROM ghcr.io/charmbracelet/vhs
+
+# install only lightweight tools for fake services
+RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
+    --mount=type=cache,target=/var/lib/apt,sharing=locked \
+    apt-get update --allow-releaseinfo-change && apt-get install -y --no-install-recommends \
+    netcat-openbsd \
+    procps \
+    socat \
+    nginx-light
+
+WORKDIR /app
+
+# copy built binary from builder
+COPY --from=builder /src/snitch /app/snitch
+
+# copy demo files
+COPY demo/demo.tape /app/demo.tape
+COPY demo/entrypoint.sh /app/entrypoint.sh
+RUN chmod +x /app/entrypoint.sh
+
+ENV TERM=xterm-256color
+ENV COLORTERM=truecolor
+
+ENTRYPOINT ["/app/entrypoint.sh"]

demo/README.md

@@ -0,0 +1,45 @@
+# Demo Recording
+
+This directory contains files for recording the snitch demo GIF in a controlled Docker environment.
+
+## Files
+
+- `Dockerfile` - builds snitch and sets up fake network services
+- `demo.tape` - VHS script that records the demo
+- `entrypoint.sh` - starts fake services before recording
+
+## Recording the Demo
+
+From the project root:
+
+```bash
+# build the demo image
+docker build -f demo/Dockerfile -t snitch-demo .
+
+# run and output demo.gif to this directory
+docker run --rm -v $(pwd)/demo:/output snitch-demo
+```
+
+The resulting `demo.gif` will be saved to this directory.
+
+## Fake Services
+
+The container runs several fake services to demonstrate snitch:
+
+| Service | Port | Protocol |
+|---------|------|----------|
+| nginx   | 80   | TCP      |
+| web app | 8080 | TCP      |
+| node    | 3000 | TCP      |
+| postgres| 5432 | TCP      |
+| redis   | 6379 | TCP      |
+| mongo   | 27017| TCP      |
+| mdns    | 5353 | UDP      |
+| ssdp    | 1900 | UDP      |
+
+Plus some simulated established connections between services.
+
+## Customizing
+
+Edit `demo.tape` to change what's shown in the demo. See [VHS documentation](https://github.com/charmbracelet/vhs) for available commands.
+

demo/demo.tape

@@ -0,0 +1,94 @@
+Output demo.gif
+
+Set Shell "bash"
+Set FontSize 14
+Set FontFamily "DejaVu Sans Mono"
+Set Width 1400
+Set Height 700
+Set Theme "Catppuccin Frappe"
+Set Padding 15
+Set Framerate 24
+Set TypingSpeed 30ms
+Set PlaybackSpeed 1.5
+
+# force color output
+Env TERM "xterm-256color"
+Env COLORTERM "truecolor"
+Env CLICOLOR "1"
+Env CLICOLOR_FORCE "1"
+Env FORCE_COLOR "1"
+
+# launch snitch
+Type "./snitch top"
+Enter
+Sleep 1s
+
+# navigate down through connections
+Down
+Sleep 200ms
+Down
+Sleep 200ms
+Down
+Sleep 200ms
+Down
+Sleep 200ms
+Down
+Sleep 600ms
+
+# open detail view for selected connection
+Enter
+Sleep 1.5s
+
+# close detail view
+Escape
+Sleep 500ms
+
+# search for nginx
+Type "/"
+Sleep 300ms
+Type "nginx"
+Sleep 600ms
+Enter
+Sleep 1.2s
+
+# clear search
+Type "/"
+Sleep 200ms
+Escape
+Sleep 500ms
+
+# filter: hide udp, show only tcp
+Type "u"
+Sleep 800ms
+
+# show only listening connections
+Type "e"
+Sleep 800ms
+Type "o"
+Sleep 800ms
+
+# reset to show all
+Type "a"
+Sleep 800ms
+
+# cycle through sort options
+Type "s"
+Sleep 500ms
+Type "s"
+Sleep 500ms
+
+# reverse sort order
+Type "S"
+Sleep 800ms
+
+# show help screen
+Type "?"
+Sleep 2s
+
+# close help
+Escape
+Sleep 500ms
+
+# quit
+Type "q"
+Sleep 200ms

demo/entrypoint.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+# entrypoint script that creates fake network services for demo
+
+set -e
+
+echo "starting demo services..."
+
+# start nginx on port 80
+nginx &
+sleep 0.5
+
+# start some listening services with socat (stderr silenced)
+socat TCP-LISTEN:8080,fork,reuseaddr SYSTEM:"echo HTTP/1.1 200 OK" 2>/dev/null &
+socat TCP-LISTEN:3000,fork,reuseaddr SYSTEM:"echo hello" 2>/dev/null &
+socat TCP-LISTEN:5432,fork,reuseaddr SYSTEM:"echo postgres" 2>/dev/null &
+socat TCP-LISTEN:6379,fork,reuseaddr SYSTEM:"echo redis" 2>/dev/null &
+socat TCP-LISTEN:27017,fork,reuseaddr SYSTEM:"echo mongo" 2>/dev/null &
+
+# create some "established" connections by connecting to our own services
+sleep 0.5
+(while true; do echo "ping" | nc -q 1 localhost 8080 2>/dev/null; sleep 2; done) >/dev/null 2>&1 &
+(while true; do echo "ping" | nc -q 1 localhost 3000 2>/dev/null; sleep 2; done) >/dev/null 2>&1 &
+(while true; do curl -s http://localhost:80 >/dev/null 2>&1; sleep 3; done) &
+
+# udp listeners
+socat UDP-LISTEN:5353,fork,reuseaddr SYSTEM:"echo mdns" 2>/dev/null &
+socat UDP-LISTEN:1900,fork,reuseaddr SYSTEM:"echo ssdp" 2>/dev/null &
+
+sleep 1
+echo "services started, recording demo..."
+
+# run vhs to record the demo
+cd /app
+vhs demo.tape
+
+echo "demo recorded, copying output..."
+
+# output will be in /app/demo.gif
+cp /app/demo.gif /output/demo.gif 2>/dev/null || echo "output copied"
+
+echo "done!"

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1756217674,
+        "lastModified": 1765687488,
-        "narHash": "sha256-TH1SfSP523QI7kcPiNtMAEuwZR3Jdz0MCDXPs7TS8uo=",
+        "narHash": "sha256-7YAJ6xgBAQ/Nr+7MI13Tui1ULflgAdKh63m1tfYV7+M=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "4e7667a90c167f7a81d906e5a75cba4ad8bee620",
+        "rev": "d02bcc33948ca19b0aaa0213fe987ceec1f4ebe1",
         "type": "github"
       },
       "original": {

flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "go 1.25.0 dev flake";
+  description = "snitch - a friendlier ss/netstat for humans";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
@@ -10,44 +10,29 @@
     let
       supportedSystems = import systems;
       forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: f system);
-    in
+
-    {
+      # go 1.25 overlay (required until nixpkgs has it)
-      overlays.default = final: prev:
+      goOverlay = final: prev:
         let
           version = "1.25.0";
-
           platformInfo = {
             "x86_64-linux" = { suffix = "linux-amd64"; sri = "sha256-KFKvDLIKExObNEiZLmm4aOUO0Pih5ZQO4d6eGaEjthM="; };
             "aarch64-linux" = { suffix = "linux-arm64"; sri = "sha256-Bd511plKJ4NpmBXuVTvVqTJ9i3mZHeNuOLZoYngvVK4="; };
-            "i686-linux" = { suffix = "linux-386"; sri = "sha256-jGAt2dmbyUU7OZXSDOS684LMUIVZAKDs5d6ZKd9KmTo="; };
-            "armv6l-linux" = { suffix = "linux-armv6l"; sri = "sha256-paj4GY/PAOHkhbjs757gIHeL8ypAik6Iczcb/ORYzQk="; };
-
             "x86_64-darwin" = { suffix = "darwin-amd64"; sri = "sha256-W9YOgjA3BiwjB8cegRGAmGURZxTW9rQQWXz1B139gO8="; };
             "aarch64-darwin" = { suffix = "darwin-arm64"; sri = "sha256-VEkyhEFW2Bcveij3fyrJwVojBGaYtiQ/YzsKCwDAdJw="; };
           };
-
           hostSystem = prev.stdenv.hostPlatform.system;
-
+          chosen = platformInfo.${hostSystem} or (throw "unsupported system: ${hostSystem}");
-          chosen =
-            if prev.lib.hasAttr hostSystem platformInfo then platformInfo.${hostSystem}
-            else
-              throw ''
-                unsupported system: ${hostSystem}
-                add a mapping for your platform using the upstream tarball + sri sha256
-              '';
         in
         {
-          go_1_25_bin = prev.stdenvNoCC.mkDerivation {
+          go_1_25 = prev.stdenvNoCC.mkDerivation {
             pname = "go";
-            version = version;
+            inherit version;
-
             src = prev.fetchurl {
               url = "https://go.dev/dl/go${version}.${chosen.suffix}.tar.gz";
               hash = chosen.sri;
             };
-
             dontBuild = true;
-
             installPhase = ''
               runHook preInstall
               mkdir -p "$out"/{bin,share}
@@ -57,35 +42,61 @@
               ln -s "$out/share/go/bin/gofmt" "$out/bin/gofmt"
               runHook postInstall
             '';
-
             dontPatchELF = true;
             dontStrip = true;
-
-            meta = with prev.lib; {
-              description = "go compiler and tools v${version}";
-              homepage = "https://go.dev/dl/";
-              license = licenses.bsd3;
-              platforms = [ hostSystem ];
           };
         };
+    in
+    {
+      overlays.default = final: prev: {
+        snitch = final.callPackage ./nix/package.nix { };
       };
 
       packages = forAllSystems (system:
-        let pkgs = import nixpkgs { inherit system; overlays = [ self.overlays.default ]; };
+        let
-        in {
+          pkgs = import nixpkgs {
-          default = pkgs.go_1_25_bin;
+            inherit system;
-          go_1_25_bin = pkgs.go_1_25_bin;
+            overlays = [ goOverlay ];
+          };
+        in
+        let
+          version = self.shortRev or self.dirtyShortRev or "dev";
+        in
+        {
+          default = pkgs.buildGoModule {
+            pname = "snitch";
+            inherit version;
+            src = self;
+            vendorHash = "sha256-fX3wOqeOgjH7AuWGxPQxJ+wbhp240CW8tiF4rVUUDzk=";
+            env.CGO_ENABLED = 0;
+            ldflags = [
+              "-s" "-w"
+              "-X snitch/cmd.Version=${version}"
+              "-X snitch/cmd.Commit=${version}"
+              "-X snitch/cmd.Date=${self.lastModifiedDate or "unknown"}"
+            ];
+            meta = with pkgs.lib; {
+              description = "a friendlier ss/netstat for humans";
+              homepage = "https://github.com/karol-broda/snitch";
+              license = licenses.mit;
+              platforms = platforms.linux;
+              mainProgram = "snitch";
+            };
+          };
         }
       );
 
       devShells = forAllSystems (system:
-        let pkgs = import nixpkgs { inherit system; overlays = [ self.overlays.default ]; };
+        let
-        in {
+          pkgs = import nixpkgs {
+            inherit system;
+            overlays = [ goOverlay ];
+          };
+        in
+        {
           default = pkgs.mkShell {
-            packages = [ pkgs.go_1_25_bin pkgs.git ];
+            packages = [ pkgs.go_1_25 pkgs.git pkgs.vhs ];
-
             GOTOOLCHAIN = "local";
-
             shellHook = ''
               echo "go toolchain: $(go version)"
             '';

go.mod

@@ -11,10 +11,13 @@ require (
 
 require (
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
-	github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc // indirect
+	github.com/aymanbagabas/go-udiff v0.3.1 // indirect
+	github.com/charmbracelet/colorprofile v0.3.2 // indirect
 	github.com/charmbracelet/lipgloss v1.1.0 // indirect
-	github.com/charmbracelet/x/ansi v0.9.3 // indirect
+	github.com/charmbracelet/x/ansi v0.10.1 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd // indirect
+	github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a // indirect
+	github.com/charmbracelet/x/exp/teatest v0.0.0-20251215102626-e0db08df7383 // indirect
 	github.com/charmbracelet/x/term v0.2.1 // indirect
 	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
 	github.com/fsnotify/fsnotify v1.7.0 // indirect
@@ -43,11 +46,11 @@ require (
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
 	go.uber.org/atomic v1.9.0 // indirect
 	go.uber.org/multierr v1.9.0 // indirect
-	golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
+	golang.org/x/exp v0.0.0-20231006140011-7918f672742d // indirect
-	golang.org/x/sync v0.15.0 // indirect
+	golang.org/x/sync v0.16.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/term v0.38.0 // indirect
-	golang.org/x/text v0.14.0 // indirect
+	golang.org/x/text v0.28.0 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,15 +1,25 @@
 github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
+github.com/aymanbagabas/go-udiff v0.3.1 h1:LV+qyBQ2pqe0u42ZsUEtPiCaUoqgA9gYRDs3vj1nolY=
+github.com/aymanbagabas/go-udiff v0.3.1/go.mod h1:G0fsKmG+P6ylD0r6N/KgQD/nWzgfnl8ZBcNLgcbrw8E=
 github.com/charmbracelet/bubbletea v1.3.6 h1:VkHIxPJQeDt0aFJIsVxw8BQdh/F/L2KKZGsK6et5taU=
 github.com/charmbracelet/bubbletea v1.3.6/go.mod h1:oQD9VCRQFF8KplacJLo28/jofOI2ToOfGYeFgBBxHOc=
 github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc h1:4pZI35227imm7yK2bGPcfpFEmuY1gc2YSTShr4iJBfs=
 github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc/go.mod h1:X4/0JoqgTIPSFcRA/P6INZzIuyqdFY5rm8tb41s9okk=
+github.com/charmbracelet/colorprofile v0.3.2 h1:9J27WdztfJQVAQKX2WOlSSRB+5gaKqqITmrvb1uTIiI=
+github.com/charmbracelet/colorprofile v0.3.2/go.mod h1:mTD5XzNeWHj8oqHb+S1bssQb7vIHbepiebQ2kPKVKbI=
 github.com/charmbracelet/lipgloss v1.1.0 h1:vYXsiLHVkK7fp74RkV7b2kq9+zDLoEU4MZoFqR/noCY=
 github.com/charmbracelet/lipgloss v1.1.0/go.mod h1:/6Q8FR2o+kj8rz4Dq0zQc3vYf7X+B0binUUBwA0aL30=
 github.com/charmbracelet/x/ansi v0.9.3 h1:BXt5DHS/MKF+LjuK4huWrC6NCvHtexww7dMayh6GXd0=
 github.com/charmbracelet/x/ansi v0.9.3/go.mod h1:3RQDQ6lDnROptfpWuUVIUG64bD2g2BgntdxH0Ya5TeE=
+github.com/charmbracelet/x/ansi v0.10.1 h1:rL3Koar5XvX0pHGfovN03f5cxLbCF2YvLeyz7D2jVDQ=
+github.com/charmbracelet/x/ansi v0.10.1/go.mod h1:3RQDQ6lDnROptfpWuUVIUG64bD2g2BgntdxH0Ya5TeE=
 github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd h1:vy0GVL4jeHEwG5YOXDmi86oYw2yuYUGqz6a8sLwg0X8=
 github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd/go.mod h1:xe0nKWGd3eJgtqZRaN9RjMtK7xUYchjzPr7q6kcvCCs=
+github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a h1:G99klV19u0QnhiizODirwVksQB91TJKV/UaTnACcG30=
+github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a/go.mod h1:wDlXFlCrmJ8J+swcL/MnGUuYnqgQdW9rhSD61oNMb6U=
+github.com/charmbracelet/x/exp/teatest v0.0.0-20251215102626-e0db08df7383 h1:nCaK/2JwS/z7GoS3cIQlNYIC6MMzWLC8zkT6JkGvkn0=
+github.com/charmbracelet/x/exp/teatest v0.0.0-20251215102626-e0db08df7383/go.mod h1:aPVjFrBwbJgj5Qz1F0IXsnbcOVJcMKgu1ySUfTAxh7k=
 github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQaGIAQ=
 github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
 github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
@@ -90,8 +100,12 @@ go.uber.org/multierr v1.9.0 h1:7fIwc/ZtS0q++VgcfqFDxSBZVv/Xo49/SYnDFupUwlI=
 go.uber.org/multierr v1.9.0/go.mod h1:X2jQV1h+kxSjClGpnseKVIxpmcjrj7MNnI0bnlfKTVQ=
 golang.org/x/exp v0.0.0-20230905200255-921286631fa9 h1:GoHiUyI/Tp2nVkLI2mCxVkOjsbSXD66ic0XW0js0R9g=
 golang.org/x/exp v0.0.0-20230905200255-921286631fa9/go.mod h1:S2oDrQGGwySpoQPVqRShND87VCbxmc6bL1Yd2oYrm6k=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
 golang.org/x/sync v0.15.0 h1:KWH3jNZsfyT6xfAfKiz6MRNmd46ByHDYaZ7KSkCtdW8=
 golang.org/x/sync v0.15.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
+golang.org/x/sync v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
+golang.org/x/sync v0.16.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
 golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -103,6 +117,8 @@ golang.org/x/term v0.38.0 h1:PQ5pkm/rLO6HnxFR7N2lJHOZX6Kez5Y1gDSJla6jo7Q=
 golang.org/x/term v0.38.0/go.mod h1:bSEAKrOT1W+VSu9TSCMtoGEOUcKxOKgl3LE5QEF/xVg=
 golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
+golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
 gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=

internal/collector/collector.go

@@ -1,17 +1,8 @@
 package collector
 
 import (
-	"bufio"
-	"bytes"
-	"fmt"
 	"net"
-	"os"
-	"os/user"
-	"path/filepath"
-	"runtime"
-	"strconv"
 	"strings"
-	"time"
 )
 
 // Collector interface defines methods for collecting connection data
@@ -19,9 +10,6 @@ type Collector interface {
 	GetConnections() ([]Connection, error)
 }
 
-// DefaultCollector implements the Collector interface using /proc
-type DefaultCollector struct{}
-
 // Global collector instance (can be overridden for testing)
 var globalCollector Collector = &DefaultCollector{}
 
@@ -40,64 +28,6 @@ func GetConnections() ([]Connection, error) {
 	return globalCollector.GetConnections()
 }
 
-// GetConnections fetches all network connections by parsing /proc files.
-func (dc *DefaultCollector) GetConnections() ([]Connection, error) {
-	if runtime.GOOS != "linux" {
-		return nil, fmt.Errorf("proc-based collector only supports Linux")
-	}
-
-	// Build map of inode -> process info by scanning /proc
-	inodeMap, err := buildInodeToProcessMap()
-	if err != nil {
-		return nil, fmt.Errorf("failed to build inode map: %w", err)
-	}
-
-	var connections []Connection
-
-	// Parse TCP connections
-	tcpConns, err := parseProcNet("/proc/net/tcp", "tcp", 4, inodeMap)
-	if err == nil {
-		connections = append(connections, tcpConns...)
-	}
-
-	tcpConns6, err := parseProcNet("/proc/net/tcp6", "tcp6", 6, inodeMap)
-	if err == nil {
-		connections = append(connections, tcpConns6...)
-	}
-
-	// Parse UDP connections
-	udpConns, err := parseProcNet("/proc/net/udp", "udp", 4, inodeMap)
-	if err == nil {
-		connections = append(connections, udpConns...)
-	}
-
-	udpConns6, err := parseProcNet("/proc/net/udp6", "udp6", 6, inodeMap)
-	if err == nil {
-		connections = append(connections, udpConns6...)
-	}
-
-	return connections, nil
-}
-
-// GetAllConnections returns both network and Unix domain socket connections
-func GetAllConnections() ([]Connection, error) {
-	// Get network connections
-	networkConns, err := GetConnections()
-	if err != nil {
-		return nil, err
-	}
-
-	// Get Unix sockets (only on Linux)
-	if runtime.GOOS == "linux" {
-		unixConns, err := GetUnixSockets()
-		if err == nil {
-			networkConns = append(networkConns, unixConns...)
-		}
-	}
-
-	return networkConns, nil
-}
-
 func FilterConnections(conns []Connection, filters FilterOptions) []Connection {
 	if filters.IsEmpty() {
 		return conns
@@ -112,395 +42,60 @@ func FilterConnections(conns []Connection, filters FilterOptions) []Connection {
 	return filtered
 }
 
-// processInfo holds information about a process
+func guessNetworkInterface(addr string) string {
-type processInfo struct {
-	pid     int
-	command string
-	uid     int
-	user    string
-}
-
-// buildInodeToProcessMap scans /proc to map socket inodes to processes
-func buildInodeToProcessMap() (map[int64]*processInfo, error) {
-	inodeMap := make(map[int64]*processInfo)
-
-	procDir, err := os.Open("/proc")
-	if err != nil {
-		return nil, err
-	}
-	defer procDir.Close()
-
-	entries, err := procDir.Readdir(-1)
-	if err != nil {
-		return nil, err
-	}
-
-	for _, entry := range entries {
-		if !entry.IsDir() {
-			continue
-		}
-
-		// check if directory name is a number (pid)
-		pidStr := entry.Name()
-		pid, err := strconv.Atoi(pidStr)
-		if err != nil {
-			continue
-		}
-
-		// get process info
-		procInfo, err := getProcessInfo(pid)
-		if err != nil {
-			continue
-		}
-
-		// scan /proc/[pid]/fd/ for socket file descriptors
-		fdDir := filepath.Join("/proc", pidStr, "fd")
-		fdEntries, err := os.ReadDir(fdDir)
-		if err != nil {
-			continue
-		}
-
-		for _, fdEntry := range fdEntries {
-			fdPath := filepath.Join(fdDir, fdEntry.Name())
-			link, err := os.Readlink(fdPath)
-			if err != nil {
-				continue
-			}
-
-			// socket inodes look like: socket:[12345]
-			if strings.HasPrefix(link, "socket:[") && strings.HasSuffix(link, "]") {
-				inodeStr := link[8 : len(link)-1]
-				inode, err := strconv.ParseInt(inodeStr, 10, 64)
-				if err != nil {
-					continue
-				}
-				inodeMap[inode] = procInfo
-			}
-		}
-	}
-
-	return inodeMap, nil
-}
-
-// getProcessInfo reads process information from /proc/[pid]/
-func getProcessInfo(pid int) (*processInfo, error) {
-	info := &processInfo{pid: pid}
-
-	// prefer /proc/[pid]/comm as it's always just the command name
-	commPath := filepath.Join("/proc", strconv.Itoa(pid), "comm")
-	commData, err := os.ReadFile(commPath)
-	if err == nil && len(commData) > 0 {
-		info.command = strings.TrimSpace(string(commData))
-	}
-
-	// if comm is not available, try cmdline
-	if info.command == "" {
-		cmdlinePath := filepath.Join("/proc", strconv.Itoa(pid), "cmdline")
-		cmdlineData, err := os.ReadFile(cmdlinePath)
-		if err != nil {
-			return nil, err
-		}
-
-		// cmdline is null-separated, take first part
-		if len(cmdlineData) > 0 {
-			parts := bytes.Split(cmdlineData, []byte{0})
-			if len(parts) > 0 && len(parts[0]) > 0 {
-				fullPath := string(parts[0])
-				// extract basename from full path
-				baseName := filepath.Base(fullPath)
-				// if basename contains spaces (single-string cmdline), take first word
-				if strings.Contains(baseName, " ") {
-					baseName = strings.Fields(baseName)[0]
-				}
-				info.command = baseName
-			}
-		}
-	}
-
-	// read UID from /proc/[pid]/status
-	statusPath := filepath.Join("/proc", strconv.Itoa(pid), "status")
-	statusFile, err := os.Open(statusPath)
-	if err != nil {
-		return info, nil
-	}
-	defer statusFile.Close()
-
-	scanner := bufio.NewScanner(statusFile)
-	for scanner.Scan() {
-		line := scanner.Text()
-		if strings.HasPrefix(line, "Uid:") {
-			fields := strings.Fields(line)
-			if len(fields) >= 2 {
-				uid, err := strconv.Atoi(fields[1])
-				if err == nil {
-					info.uid = uid
-					// get username from uid
-					u, err := user.LookupId(strconv.Itoa(uid))
-					if err == nil {
-						info.user = u.Username
-					} else {
-						info.user = strconv.Itoa(uid)
-					}
-				}
-			}
-			break
-		}
-	}
-
-	return info, nil
-}
-
-// parseProcNet parses a /proc/net/tcp or /proc/net/udp file
-func parseProcNet(path, proto string, ipVersion int, inodeMap map[int64]*processInfo) ([]Connection, error) {
-	file, err := os.Open(path)
-	if err != nil {
-		return nil, err
-	}
-	defer file.Close()
-
-	var connections []Connection
-	scanner := bufio.NewScanner(file)
-
-	// skip header
-	scanner.Scan()
-
-	for scanner.Scan() {
-		line := strings.TrimSpace(scanner.Text())
-		if line == "" {
-			continue
-		}
-
-		fields := strings.Fields(line)
-		if len(fields) < 10 {
-			continue
-		}
-
-		// parse local address and port
-		localAddr, localPort, err := parseHexAddr(fields[1])
-		if err != nil {
-			continue
-		}
-
-		// parse remote address and port
-		remoteAddr, remotePort, err := parseHexAddr(fields[2])
-		if err != nil {
-			continue
-		}
-
-		// parse state (field 3)
-		stateHex := fields[3]
-		state := parseState(stateHex, proto)
-
-		// parse inode (field 9)
-		inode, _ := strconv.ParseInt(fields[9], 10, 64)
-
-		conn := Connection{
-			TS:        time.Now(),
-			Proto:     proto,
-			IPVersion: fmt.Sprintf("IPv%d", ipVersion),
-			State:     state,
-			Laddr:     localAddr,
-			Lport:     localPort,
-			Raddr:     remoteAddr,
-			Rport:     remotePort,
-			Inode:     inode,
-		}
-
-		// add process info if available
-		if procInfo, exists := inodeMap[inode]; exists {
-			conn.PID = procInfo.pid
-			conn.Process = procInfo.command
-			conn.UID = procInfo.uid
-			conn.User = procInfo.user
-		}
-
-		// determine interface
-		conn.Interface = guessNetworkInterface(localAddr, nil)
-
-		connections = append(connections, conn)
-	}
-
-	return connections, scanner.Err()
-}
-
-// parseState converts hex state value to string
-func parseState(hexState, proto string) string {
-	state, err := strconv.ParseInt(hexState, 16, 32)
-	if err != nil {
-		return ""
-	}
-
-	// TCP states
-	tcpStates := map[int64]string{
-		0x01: "ESTABLISHED",
-		0x02: "SYN_SENT",
-		0x03: "SYN_RECV",
-		0x04: "FIN_WAIT1",
-		0x05: "FIN_WAIT2",
-		0x06: "TIME_WAIT",
-		0x07: "CLOSE",
-		0x08: "CLOSE_WAIT",
-		0x09: "LAST_ACK",
-		0x0A: "LISTEN",
-		0x0B: "CLOSING",
-	}
-
-	if strings.HasPrefix(proto, "tcp") {
-		if s, exists := tcpStates[state]; exists {
-			return s
-		}
-	} else {
-		// UDP doesn't have states in the same way
-		if state == 0x07 {
-			return "CLOSE"
-		}
-		return ""
-	}
-
-	return ""
-}
-
-// parseHexAddr parses hex-encoded address:port from /proc/net files
-func parseHexAddr(hexAddr string) (string, int, error) {
-	parts := strings.Split(hexAddr, ":")
-	if len(parts) != 2 {
-		return "", 0, fmt.Errorf("invalid address format")
-	}
-
-	hexIP := parts[0]
-
-	// parse hex port
-	port, err := strconv.ParseInt(parts[1], 16, 32)
-	if err != nil {
-		return "", 0, err
-	}
-
-	if len(hexIP) == 8 {
-		// IPv4 (stored in little-endian)
-		ip1, _ := strconv.ParseInt(hexIP[6:8], 16, 32)
-		ip2, _ := strconv.ParseInt(hexIP[4:6], 16, 32)
-		ip3, _ := strconv.ParseInt(hexIP[2:4], 16, 32)
-		ip4, _ := strconv.ParseInt(hexIP[0:2], 16, 32)
-		addr := fmt.Sprintf("%d.%d.%d.%d", ip1, ip2, ip3, ip4)
-
-		// handle wildcard address
-		if addr == "0.0.0.0" {
-			addr = "*"
-		}
-
-		return addr, int(port), nil
-	} else if len(hexIP) == 32 {
-		// IPv6 (stored in little-endian per 32-bit word)
-		var ipv6Parts []string
-		for i := 0; i < 32; i += 8 {
-			word := hexIP[i : i+8]
-			// reverse byte order within each 32-bit word
-			p1 := word[6:8] + word[4:6] + word[2:4] + word[0:2]
-			ipv6Parts = append(ipv6Parts, p1)
-		}
-
-		// convert to standard IPv6 notation
-		fullAddr := strings.Join(ipv6Parts, "")
-		var formatted []string
-		for i := 0; i < len(fullAddr); i += 4 {
-			formatted = append(formatted, fullAddr[i:i+4])
-		}
-		addr := strings.Join(formatted, ":")
-
-		// simplify IPv6 address
-		addr = simplifyIPv6(addr)
-
-		// handle wildcard address
-		if addr == "::" || addr == "0:0:0:0:0:0:0:0" {
-			addr = "*"
-		}
-
-		return addr, int(port), nil
-	}
-
-	return "", 0, fmt.Errorf("unsupported address format")
-}
-
-// simplifyIPv6 simplifies IPv6 address notation
-func simplifyIPv6(addr string) string {
-	// remove leading zeros from each group
-	parts := strings.Split(addr, ":")
-	for i, part := range parts {
-		// convert to int and back to remove leading zeros
-		val, err := strconv.ParseInt(part, 16, 64)
-		if err == nil {
-			parts[i] = strconv.FormatInt(val, 16)
-		}
-	}
-	return strings.Join(parts, ":")
-}
-
-func guessNetworkInterface(addr string, interfaces map[string]string) string {
-	// Simple heuristic - try to match common interface patterns
 	if addr == "127.0.0.1" || addr == "::1" {
 		return "lo"
 	}
 
-	// Check if it's a private network address
 	ip := net.ParseIP(addr)
-	if ip != nil {
+	if ip == nil {
+		return ""
+	}
+
 	if ip.IsLoopback() {
 		return "lo"
 	}
-		// More sophisticated interface detection would require routing table analysis
-		// For now, return a placeholder
-		if ip.To4() != nil {
-			return "eth0" // Common default for IPv4
-		} else {
-			return "eth0" // Common default for IPv6
-		}
-	}
 
+	// default interface name varies by OS but we return a generic value
+	// actual interface detection would require routing table analysis
 	return ""
 }
 
-// Add Unix socket support
+func simplifyIPv6(addr string) string {
-func GetUnixSockets() ([]Connection, error) {
+	parts := strings.Split(addr, ":")
-	connections := []Connection{}
+	for i, part := range parts {
-
+		// parse as hex then format back to remove leading zeros
-	// Parse /proc/net/unix for Unix domain sockets
+		var val int64
-	file, err := os.Open("/proc/net/unix")
+		for _, c := range part {
-	if err != nil {
+			val = val*16 + int64(hexCharToInt(c))
-		return connections, nil // silently fail on non-Linux systems
 		}
-	defer file.Close()
+		parts[i] = formatHex(val)
-
-	scanner := bufio.NewScanner(file)
-	// Skip header
-	scanner.Scan()
-
-	for scanner.Scan() {
-		line := strings.TrimSpace(scanner.Text())
-		fields := strings.Fields(line)
-		if len(fields) < 7 {
-			continue
 	}
-
+	return strings.Join(parts, ":")
-		// Parse Unix socket information
-		inode, _ := strconv.ParseInt(fields[6], 10, 64)
-		path := ""
-		if len(fields) > 7 {
-			path = fields[7]
-		}
-
-		conn := Connection{
-			TS:        time.Now(),
-			Proto:     "unix",
-			Laddr:     path,
-			Raddr:     "",
-			State:     "CONNECTED", // Simplified
-			Inode:     inode,
-			Interface: "unix",
-		}
-
-		connections = append(connections, conn)
-	}
-
-	return connections, nil
 }
 
+func hexCharToInt(c rune) int {
+	switch {
+	case c >= '0' && c <= '9':
+		return int(c - '0')
+	case c >= 'a' && c <= 'f':
+		return int(c - 'a' + 10)
+	case c >= 'A' && c <= 'F':
+		return int(c - 'A' + 10)
+	default:
+		return 0
+	}
+}
+
+func formatHex(val int64) string {
+	if val == 0 {
+		return "0"
+	}
+	const hexDigits = "0123456789abcdef"
+	var result []byte
+	for val > 0 {
+		result = append([]byte{hexDigits[val%16]}, result...)
+		val /= 16
+	}
+	return string(result)
+}

internal/collector/collector_darwin.go

@@ -0,0 +1,338 @@
+//go:build darwin
+
+package collector
+
+/*
+#include <libproc.h>
+#include <sys/proc_info.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/tcp_fsm.h>
+#include <arpa/inet.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <string.h>
+
+// get process name by pid
+static int get_proc_name(int pid, char *name, int namelen) {
+    return proc_name(pid, name, namelen);
+}
+
+// get uid for a process
+static int get_proc_uid(int pid) {
+    struct proc_bsdinfo info;
+    int ret = proc_pidinfo(pid, PROC_PIDTBSDINFO, 0, &info, sizeof(info));
+    if (ret <= 0) {
+        return -1;
+    }
+    return info.pbi_uid;
+}
+
+// get username from uid
+static const char* get_username(int uid) {
+    struct passwd *pw = getpwuid(uid);
+    if (pw == NULL) {
+        return NULL;
+    }
+    return pw->pw_name;
+}
+
+// socket info extraction - handles the union properly in C
+typedef struct {
+    int family;
+    int sock_type;
+    int protocol;
+    int state;
+    uint32_t laddr4;
+    uint32_t raddr4;
+    uint8_t laddr6[16];
+    uint8_t raddr6[16];
+    int lport;
+    int rport;
+} socket_info_t;
+
+static int get_socket_info(int pid, int fd, socket_info_t *info) {
+    struct socket_fdinfo si;
+    int ret = proc_pidfdinfo(pid, fd, PROC_PIDFDSOCKETINFO, &si, sizeof(si));
+    if (ret <= 0) {
+        return -1;
+    }
+
+    info->family = si.psi.soi_family;
+    info->sock_type = si.psi.soi_type;
+    info->protocol = si.psi.soi_protocol;
+
+    if (info->family == AF_INET) {
+        if (info->sock_type == SOCK_STREAM) {
+            // TCP
+            info->state = si.psi.soi_proto.pri_tcp.tcpsi_state;
+            info->laddr4 = si.psi.soi_proto.pri_tcp.tcpsi_ini.insi_laddr.ina_46.i46a_addr4.s_addr;
+            info->raddr4 = si.psi.soi_proto.pri_tcp.tcpsi_ini.insi_faddr.ina_46.i46a_addr4.s_addr;
+            info->lport = ntohs(si.psi.soi_proto.pri_tcp.tcpsi_ini.insi_lport);
+            info->rport = ntohs(si.psi.soi_proto.pri_tcp.tcpsi_ini.insi_fport);
+        } else if (info->sock_type == SOCK_DGRAM) {
+            // UDP
+            info->state = 0;
+            info->laddr4 = si.psi.soi_proto.pri_in.insi_laddr.ina_46.i46a_addr4.s_addr;
+            info->raddr4 = si.psi.soi_proto.pri_in.insi_faddr.ina_46.i46a_addr4.s_addr;
+            info->lport = ntohs(si.psi.soi_proto.pri_in.insi_lport);
+            info->rport = ntohs(si.psi.soi_proto.pri_in.insi_fport);
+        }
+    } else if (info->family == AF_INET6) {
+        if (info->sock_type == SOCK_STREAM) {
+            // TCP6
+            info->state = si.psi.soi_proto.pri_tcp.tcpsi_state;
+            memcpy(info->laddr6, &si.psi.soi_proto.pri_tcp.tcpsi_ini.insi_laddr.ina_6, 16);
+            memcpy(info->raddr6, &si.psi.soi_proto.pri_tcp.tcpsi_ini.insi_faddr.ina_6, 16);
+            info->lport = ntohs(si.psi.soi_proto.pri_tcp.tcpsi_ini.insi_lport);
+            info->rport = ntohs(si.psi.soi_proto.pri_tcp.tcpsi_ini.insi_fport);
+        } else if (info->sock_type == SOCK_DGRAM) {
+            // UDP6
+            info->state = 0;
+            memcpy(info->laddr6, &si.psi.soi_proto.pri_in.insi_laddr.ina_6, 16);
+            memcpy(info->raddr6, &si.psi.soi_proto.pri_in.insi_faddr.ina_6, 16);
+            info->lport = ntohs(si.psi.soi_proto.pri_in.insi_lport);
+            info->rport = ntohs(si.psi.soi_proto.pri_in.insi_fport);
+        }
+    }
+
+    return 0;
+}
+*/
+import "C"
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+	"time"
+	"unsafe"
+)
+
+// DefaultCollector implements the Collector interface using libproc on macOS
+type DefaultCollector struct{}
+
+// GetConnections fetches all network connections using libproc
+func (dc *DefaultCollector) GetConnections() ([]Connection, error) {
+	pids, err := listAllPids()
+	if err != nil {
+		return nil, fmt.Errorf("failed to list pids: %w", err)
+	}
+
+	var connections []Connection
+
+	for _, pid := range pids {
+		procConns, err := getConnectionsForPid(pid)
+		if err != nil {
+			continue
+		}
+		connections = append(connections, procConns...)
+	}
+
+	return connections, nil
+}
+
+// GetAllConnections returns network connections
+func GetAllConnections() ([]Connection, error) {
+	return GetConnections()
+}
+
+func listAllPids() ([]int, error) {
+	numPids := C.proc_listpids(C.PROC_ALL_PIDS, 0, nil, 0)
+	if numPids <= 0 {
+		return nil, fmt.Errorf("proc_listpids failed")
+	}
+
+	bufSize := C.int(numPids) * C.int(unsafe.Sizeof(C.int(0)))
+	buf := make([]C.int, numPids)
+
+	numPids = C.proc_listpids(C.PROC_ALL_PIDS, 0, unsafe.Pointer(&buf[0]), bufSize)
+	if numPids <= 0 {
+		return nil, fmt.Errorf("proc_listpids failed")
+	}
+
+	count := int(numPids) / int(unsafe.Sizeof(C.int(0)))
+	pids := make([]int, 0, count)
+	for i := 0; i < count; i++ {
+		if buf[i] > 0 {
+			pids = append(pids, int(buf[i]))
+		}
+	}
+
+	return pids, nil
+}
+
+func getConnectionsForPid(pid int) ([]Connection, error) {
+	procName := getProcessName(pid)
+	uid := int(C.get_proc_uid(C.int(pid)))
+	user := ""
+	if uid >= 0 {
+		cUser := C.get_username(C.int(uid))
+		if cUser != nil {
+			user = C.GoString(cUser)
+		} else {
+			user = strconv.Itoa(uid)
+		}
+	}
+
+	bufSize := C.proc_pidinfo(C.int(pid), C.PROC_PIDLISTFDS, 0, nil, 0)
+	if bufSize <= 0 {
+		return nil, fmt.Errorf("failed to get fd list size")
+	}
+
+	buf := make([]byte, bufSize)
+	ret := C.proc_pidinfo(C.int(pid), C.PROC_PIDLISTFDS, 0, unsafe.Pointer(&buf[0]), bufSize)
+	if ret <= 0 {
+		return nil, fmt.Errorf("failed to get fd list")
+	}
+
+	fdInfoSize := int(unsafe.Sizeof(C.struct_proc_fdinfo{}))
+	numFds := int(ret) / fdInfoSize
+
+	var connections []Connection
+
+	for i := 0; i < numFds; i++ {
+		fdInfo := (*C.struct_proc_fdinfo)(unsafe.Pointer(&buf[i*fdInfoSize]))
+
+		if fdInfo.proc_fdtype != C.PROX_FDTYPE_SOCKET {
+			continue
+		}
+
+		conn, ok := getSocketInfo(pid, int(fdInfo.proc_fd), procName, uid, user)
+		if ok {
+			connections = append(connections, conn)
+		}
+	}
+
+	return connections, nil
+}
+
+func getSocketInfo(pid, fd int, procName string, uid int, user string) (Connection, bool) {
+	var info C.socket_info_t
+
+	ret := C.get_socket_info(C.int(pid), C.int(fd), &info)
+	if ret != 0 {
+		return Connection{}, false
+	}
+
+	// only interested in IPv4 and IPv6
+	if info.family != C.AF_INET && info.family != C.AF_INET6 {
+		return Connection{}, false
+	}
+
+	// only TCP and UDP
+	if info.sock_type != C.SOCK_STREAM && info.sock_type != C.SOCK_DGRAM {
+		return Connection{}, false
+	}
+
+	proto := "tcp"
+	if info.sock_type == C.SOCK_DGRAM {
+		proto = "udp"
+	}
+
+	ipVersion := "IPv4"
+	if info.family == C.AF_INET6 {
+		ipVersion = "IPv6"
+		proto = proto + "6"
+	}
+
+	var laddr, raddr string
+
+	if info.family == C.AF_INET {
+		laddr = ipv4ToString(uint32(info.laddr4))
+		raddr = ipv4ToString(uint32(info.raddr4))
+	} else {
+		laddr = ipv6ToString(info.laddr6)
+		raddr = ipv6ToString(info.raddr6)
+	}
+
+	if laddr == "0.0.0.0" || laddr == "::" {
+		laddr = "*"
+	}
+	if raddr == "0.0.0.0" || raddr == "::" {
+		raddr = "*"
+	}
+
+	state := ""
+	if info.sock_type == C.SOCK_STREAM {
+		state = tcpStateToString(int(info.state))
+	} else if info.sock_type == C.SOCK_DGRAM {
+		// udp is connectionless - infer state from remote address
+		if raddr == "*" && int(info.rport) == 0 {
+			state = "LISTEN"
+		} else {
+			state = "ESTABLISHED"
+		}
+	}
+
+	conn := Connection{
+		TS:        time.Now(),
+		Proto:     proto,
+		IPVersion: ipVersion,
+		State:     state,
+		Laddr:     laddr,
+		Lport:     int(info.lport),
+		Raddr:     raddr,
+		Rport:     int(info.rport),
+		PID:       pid,
+		Process:   procName,
+		UID:       uid,
+		User:      user,
+		Interface: guessNetworkInterface(laddr),
+	}
+
+	return conn, true
+}
+
+func getProcessName(pid int) string {
+	var name [256]C.char
+	ret := C.get_proc_name(C.int(pid), &name[0], 256)
+	if ret <= 0 {
+		return ""
+	}
+	return C.GoString(&name[0])
+}
+
+func ipv4ToString(addr uint32) string {
+	ip := make(net.IP, 4)
+	ip[0] = byte(addr)
+	ip[1] = byte(addr >> 8)
+	ip[2] = byte(addr >> 16)
+	ip[3] = byte(addr >> 24)
+	return ip.String()
+}
+
+func ipv6ToString(addr [16]C.uint8_t) string {
+	ip := make(net.IP, 16)
+	for i := 0; i < 16; i++ {
+		ip[i] = byte(addr[i])
+	}
+
+	if ip.To4() != nil {
+		return ip.To4().String()
+	}
+
+	return ip.String()
+}
+
+func tcpStateToString(state int) string {
+	// macOS TCP states from netinet/tcp_fsm.h
+	states := map[int]string{
+		0:  "CLOSED",
+		1:  "LISTEN",
+		2:  "SYN_SENT",
+		3:  "SYN_RECV",
+		4:  "ESTABLISHED",
+		5:  "CLOSE_WAIT",
+		6:  "FIN_WAIT1",
+		7:  "CLOSING",
+		8:  "LAST_ACK",
+		9:  "FIN_WAIT2",
+		10: "TIME_WAIT",
+	}
+
+	if s, exists := states[state]; exists {
+		return s
+	}
+	return ""
+}

internal/collector/collector_linux.go

@@ -0,0 +1,398 @@
+//go:build linux
+
+package collector
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"os"
+	"os/user"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// DefaultCollector implements the Collector interface using /proc filesystem
+type DefaultCollector struct{}
+
+// GetConnections fetches all network connections by parsing /proc files
+func (dc *DefaultCollector) GetConnections() ([]Connection, error) {
+	inodeMap, err := buildInodeToProcessMap()
+	if err != nil {
+		return nil, fmt.Errorf("failed to build inode map: %w", err)
+	}
+
+	var connections []Connection
+
+	tcpConns, err := parseProcNet("/proc/net/tcp", "tcp", 4, inodeMap)
+	if err == nil {
+		connections = append(connections, tcpConns...)
+	}
+
+	tcpConns6, err := parseProcNet("/proc/net/tcp6", "tcp6", 6, inodeMap)
+	if err == nil {
+		connections = append(connections, tcpConns6...)
+	}
+
+	udpConns, err := parseProcNet("/proc/net/udp", "udp", 4, inodeMap)
+	if err == nil {
+		connections = append(connections, udpConns...)
+	}
+
+	udpConns6, err := parseProcNet("/proc/net/udp6", "udp6", 6, inodeMap)
+	if err == nil {
+		connections = append(connections, udpConns6...)
+	}
+
+	return connections, nil
+}
+
+// GetAllConnections returns both network and Unix domain socket connections
+func GetAllConnections() ([]Connection, error) {
+	networkConns, err := GetConnections()
+	if err != nil {
+		return nil, err
+	}
+
+	unixConns, err := GetUnixSockets()
+	if err == nil {
+		networkConns = append(networkConns, unixConns...)
+	}
+
+	return networkConns, nil
+}
+
+type processInfo struct {
+	pid     int
+	command string
+	uid     int
+	user    string
+}
+
+func buildInodeToProcessMap() (map[int64]*processInfo, error) {
+	inodeMap := make(map[int64]*processInfo)
+
+	procDir, err := os.Open("/proc")
+	if err != nil {
+		return nil, err
+	}
+	defer procDir.Close()
+
+	entries, err := procDir.Readdir(-1)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+
+		pidStr := entry.Name()
+		pid, err := strconv.Atoi(pidStr)
+		if err != nil {
+			continue
+		}
+
+		procInfo, err := getProcessInfo(pid)
+		if err != nil {
+			continue
+		}
+
+		fdDir := filepath.Join("/proc", pidStr, "fd")
+		fdEntries, err := os.ReadDir(fdDir)
+		if err != nil {
+			continue
+		}
+
+		for _, fdEntry := range fdEntries {
+			fdPath := filepath.Join(fdDir, fdEntry.Name())
+			link, err := os.Readlink(fdPath)
+			if err != nil {
+				continue
+			}
+
+			if strings.HasPrefix(link, "socket:[") && strings.HasSuffix(link, "]") {
+				inodeStr := link[8 : len(link)-1]
+				inode, err := strconv.ParseInt(inodeStr, 10, 64)
+				if err != nil {
+					continue
+				}
+				inodeMap[inode] = procInfo
+			}
+		}
+	}
+
+	return inodeMap, nil
+}
+
+func getProcessInfo(pid int) (*processInfo, error) {
+	info := &processInfo{pid: pid}
+
+	commPath := filepath.Join("/proc", strconv.Itoa(pid), "comm")
+	commData, err := os.ReadFile(commPath)
+	if err == nil && len(commData) > 0 {
+		info.command = strings.TrimSpace(string(commData))
+	}
+
+	if info.command == "" {
+		cmdlinePath := filepath.Join("/proc", strconv.Itoa(pid), "cmdline")
+		cmdlineData, err := os.ReadFile(cmdlinePath)
+		if err != nil {
+			return nil, err
+		}
+
+		if len(cmdlineData) > 0 {
+			parts := bytes.Split(cmdlineData, []byte{0})
+			if len(parts) > 0 && len(parts[0]) > 0 {
+				fullPath := string(parts[0])
+				baseName := filepath.Base(fullPath)
+				if strings.Contains(baseName, " ") {
+					baseName = strings.Fields(baseName)[0]
+				}
+				info.command = baseName
+			}
+		}
+	}
+
+	statusPath := filepath.Join("/proc", strconv.Itoa(pid), "status")
+	statusFile, err := os.Open(statusPath)
+	if err != nil {
+		return info, nil
+	}
+	defer statusFile.Close()
+
+	scanner := bufio.NewScanner(statusFile)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "Uid:") {
+			fields := strings.Fields(line)
+			if len(fields) >= 2 {
+				uid, err := strconv.Atoi(fields[1])
+				if err == nil {
+					info.uid = uid
+					u, err := user.LookupId(strconv.Itoa(uid))
+					if err == nil {
+						info.user = u.Username
+					} else {
+						info.user = strconv.Itoa(uid)
+					}
+				}
+			}
+			break
+		}
+	}
+
+	return info, nil
+}
+
+func parseProcNet(path, proto string, ipVersion int, inodeMap map[int64]*processInfo) ([]Connection, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	var connections []Connection
+	scanner := bufio.NewScanner(file)
+
+	scanner.Scan()
+
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" {
+			continue
+		}
+
+		fields := strings.Fields(line)
+		if len(fields) < 10 {
+			continue
+		}
+
+		localAddr, localPort, err := parseHexAddr(fields[1])
+		if err != nil {
+			continue
+		}
+
+		remoteAddr, remotePort, err := parseHexAddr(fields[2])
+		if err != nil {
+			continue
+		}
+
+		stateHex := fields[3]
+		state := parseState(stateHex, proto)
+
+		inode, _ := strconv.ParseInt(fields[9], 10, 64)
+
+		// refine udp state: if unconnected and remote is wildcard, it's listening
+		if strings.HasPrefix(proto, "udp") && state == "UNCONNECTED" {
+			if remoteAddr == "*" && remotePort == 0 {
+				state = "LISTEN"
+			}
+		}
+
+		conn := Connection{
+			TS:        time.Now(),
+			Proto:     proto,
+			IPVersion: fmt.Sprintf("IPv%d", ipVersion),
+			State:     state,
+			Laddr:     localAddr,
+			Lport:     localPort,
+			Raddr:     remoteAddr,
+			Rport:     remotePort,
+			Inode:     inode,
+		}
+
+		if procInfo, exists := inodeMap[inode]; exists {
+			conn.PID = procInfo.pid
+			conn.Process = procInfo.command
+			conn.UID = procInfo.uid
+			conn.User = procInfo.user
+		}
+
+		conn.Interface = guessNetworkInterface(localAddr)
+
+		connections = append(connections, conn)
+	}
+
+	return connections, scanner.Err()
+}
+
+func parseState(hexState, proto string) string {
+	state, err := strconv.ParseInt(hexState, 16, 32)
+	if err != nil {
+		return ""
+	}
+
+	tcpStates := map[int64]string{
+		0x01: "ESTABLISHED",
+		0x02: "SYN_SENT",
+		0x03: "SYN_RECV",
+		0x04: "FIN_WAIT1",
+		0x05: "FIN_WAIT2",
+		0x06: "TIME_WAIT",
+		0x07: "CLOSE",
+		0x08: "CLOSE_WAIT",
+		0x09: "LAST_ACK",
+		0x0A: "LISTEN",
+		0x0B: "CLOSING",
+	}
+
+	if strings.HasPrefix(proto, "tcp") {
+		if s, exists := tcpStates[state]; exists {
+			return s
+		}
+		return ""
+	}
+
+	// udp states - udp is connectionless so the kernel reuses tcp state values
+	// with different meanings:
+	// 0x07 (TCP_CLOSE) = unconnected socket, typically bound and listening
+	// 0x01 (TCP_ESTABLISHED) = "connected" socket (connect() was called)
+	udpStates := map[int64]string{
+		0x01: "ESTABLISHED",
+		0x07: "UNCONNECTED",
+	}
+
+	if s, exists := udpStates[state]; exists {
+		return s
+	}
+
+	return ""
+}
+
+func parseHexAddr(hexAddr string) (string, int, error) {
+	parts := strings.Split(hexAddr, ":")
+	if len(parts) != 2 {
+		return "", 0, fmt.Errorf("invalid address format")
+	}
+
+	hexIP := parts[0]
+
+	port, err := strconv.ParseInt(parts[1], 16, 32)
+	if err != nil {
+		return "", 0, err
+	}
+
+	if len(hexIP) == 8 {
+		ip1, _ := strconv.ParseInt(hexIP[6:8], 16, 32)
+		ip2, _ := strconv.ParseInt(hexIP[4:6], 16, 32)
+		ip3, _ := strconv.ParseInt(hexIP[2:4], 16, 32)
+		ip4, _ := strconv.ParseInt(hexIP[0:2], 16, 32)
+		addr := fmt.Sprintf("%d.%d.%d.%d", ip1, ip2, ip3, ip4)
+
+		if addr == "0.0.0.0" {
+			addr = "*"
+		}
+
+		return addr, int(port), nil
+	} else if len(hexIP) == 32 {
+		var ipv6Parts []string
+		for i := 0; i < 32; i += 8 {
+			word := hexIP[i : i+8]
+			p1 := word[6:8] + word[4:6] + word[2:4] + word[0:2]
+			ipv6Parts = append(ipv6Parts, p1)
+		}
+
+		fullAddr := strings.Join(ipv6Parts, "")
+		var formatted []string
+		for i := 0; i < len(fullAddr); i += 4 {
+			formatted = append(formatted, fullAddr[i:i+4])
+		}
+		addr := strings.Join(formatted, ":")
+
+		addr = simplifyIPv6(addr)
+
+		if addr == "::" || addr == "0:0:0:0:0:0:0:0" {
+			addr = "*"
+		}
+
+		return addr, int(port), nil
+	}
+
+	return "", 0, fmt.Errorf("unsupported address format")
+}
+
+func GetUnixSockets() ([]Connection, error) {
+	connections := []Connection{}
+
+	file, err := os.Open("/proc/net/unix")
+	if err != nil {
+		return connections, nil
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	scanner.Scan()
+
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		fields := strings.Fields(line)
+		if len(fields) < 7 {
+			continue
+		}
+
+		inode, _ := strconv.ParseInt(fields[6], 10, 64)
+		path := ""
+		if len(fields) > 7 {
+			path = fields[7]
+		}
+
+		conn := Connection{
+			TS:        time.Now(),
+			Proto:     "unix",
+			Laddr:     path,
+			Raddr:     "",
+			State:     "CONNECTED",
+			Inode:     inode,
+			Interface: "unix",
+		}
+
+		connections = append(connections, conn)
+	}
+
+	return connections, nil
+}
+

internal/collector/filter.go

@@ -36,7 +36,7 @@ func (f *FilterOptions) IsEmpty() bool {
 }
 
 func (f *FilterOptions) Matches(c Connection) bool {
-	if f.Proto != "" && !strings.EqualFold(c.Proto, f.Proto) {
+	if f.Proto != "" && !matchesProto(c.Proto, f.Proto) {
 		return false
 	}
 	if f.State != "" && !strings.EqualFold(c.State, f.State) {
@@ -104,6 +104,30 @@ func containsIgnoreCase(s, substr string) bool {
 	return strings.Contains(strings.ToLower(s), strings.ToLower(substr))
 }
 
+// checks if a connection's protocol matches the filter.
+// treats "tcp" as matching "tcp" and "tcp6", same for "udp"/"udp6"
+func matchesProto(connProto, filterProto string) bool {
+	connLower := strings.ToLower(connProto)
+	filterLower := strings.ToLower(filterProto)
+
+	// exact match
+	if connLower == filterLower {
+		return true
+	}
+
+	// "tcp" matches both "tcp" and "tcp6"
+	if filterLower == "tcp" && (connLower == "tcp" || connLower == "tcp6") {
+		return true
+	}
+
+	// "udp" matches both "udp" and "udp6"
+	if filterLower == "udp" && (connLower == "udp" || connLower == "udp6") {
+		return true
+	}
+
+	return false
+}
+
 func matchesContains(c Connection, query string) bool {
 	q := strings.ToLower(query)
 	return containsIgnoreCase(c.Process, q) ||

internal/collector/mock.go

@@ -162,7 +162,7 @@ func getDefaultTestConnections() []Connection {
 			UID:       25,
 			Proto:     "udp",
 			IPVersion: "IPv4",
-			State:     "CONNECTED",
+			State:     "LISTEN",
 			Laddr:     "0.0.0.0",
 			Lport:     53,
 			Raddr:     "*",
@@ -358,7 +358,7 @@ func GetTestFixtures() []TestFixture {
 					PID:       2,
 					Process:   "udp-server",
 					Proto:     "udp",
-					State:     "CONNECTED",
+					State:     "LISTEN",
 					Laddr:     "0.0.0.0",
 					Lport:     53,
 					Interface: "eth0",

internal/collector/sort.go

@@ -111,16 +111,17 @@ func compareConnections(a, b Connection, field SortField) bool {
 func stateOrder(state string) int {
 	order := map[string]int{
 		"LISTEN":      0,
-		"ESTABLISHED": 1,
+		"UNCONNECTED": 1, // udp sockets bound but not connected to a specific peer
-		"SYN_SENT":    2,
+		"ESTABLISHED": 2,
-		"SYN_RECV":    3,
+		"SYN_SENT":    3,
-		"FIN_WAIT1":   4,
+		"SYN_RECV":    4,
-		"FIN_WAIT2":   5,
+		"FIN_WAIT1":   5,
-		"TIME_WAIT":   6,
+		"FIN_WAIT2":   6,
-		"CLOSE_WAIT":  7,
+		"TIME_WAIT":   7,
-		"LAST_ACK":    8,
+		"CLOSE_WAIT":  8,
-		"CLOSING":     9,
+		"LAST_ACK":    9,
-		"CLOSED":      10,
+		"CLOSING":     10,
+		"CLOSED":      11,
 	}
 
 	if o, exists := order[strings.ToUpper(state)]; exists {

internal/tui/helpers.go

@@ -14,7 +14,7 @@ func truncate(s string, max int) string {
 	if max <= 2 {
 		return s[:max]
 	}
-	return s[:max-1] + "…"
+	return s[:max-1] + SymbolEllipsis
 }
 
 var ansiRegex = regexp.MustCompile(`\x1b\[[0-9;]*m`)

internal/tui/keys.go

@@ -1,7 +1,9 @@
 package tui
 
 import (
+	"fmt"
 	"snitch/internal/collector"
+	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
 )
@@ -12,6 +14,11 @@ func (m model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		return m.handleSearchKey(msg)
 	}
 
+	// kill confirmation dialog
+	if m.showKillConfirm {
+		return m.handleKillConfirmKey(msg)
+	}
+
 	// detail view only allows closing
 	if m.showDetail {
 		return m.handleDetailKey(msg)
@@ -62,6 +69,25 @@ func (m model) handleHelpKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+func (m model) handleKillConfirmKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
+	switch msg.String() {
+	case "y", "Y":
+		if m.killTarget != nil && m.killTarget.PID > 0 {
+			pid := m.killTarget.PID
+			process := m.killTarget.Process
+			m.showKillConfirm = false
+			m.killTarget = nil
+			return m, killProcess(pid, process)
+		}
+		m.showKillConfirm = false
+		m.killTarget = nil
+	case "n", "N", "esc", "q":
+		m.showKillConfirm = false
+		m.killTarget = nil
+	}
+	return m, nil
+}
+
 func (m model) handleNormalKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	switch msg.String() {
 	case "q", "ctrl+c":
@@ -135,6 +161,55 @@ func (m model) handleNormalKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		return m, m.fetchData()
 	case "?":
 		m.showHelp = true
+
+	// watch/monitor process
+	case "w":
+		visible := m.visibleConnections()
+		if m.cursor < len(visible) {
+			conn := visible[m.cursor]
+			if conn.PID > 0 {
+				wasWatched := m.isWatched(conn.PID)
+				m.toggleWatch(conn.PID)
+
+				// count connections for this pid
+				connCount := 0
+				for _, c := range m.connections {
+					if c.PID == conn.PID {
+						connCount++
+					}
+				}
+
+				if wasWatched {
+					m.statusMessage = fmt.Sprintf("unwatched %s (pid %d)", conn.Process, conn.PID)
+				} else if connCount > 1 {
+					m.statusMessage = fmt.Sprintf("watching %s (pid %d) - %d connections", conn.Process, conn.PID, connCount)
+				} else {
+					m.statusMessage = fmt.Sprintf("watching %s (pid %d)", conn.Process, conn.PID)
+				}
+				m.statusExpiry = time.Now().Add(2 * time.Second)
+				return m, clearStatusAfter(2 * time.Second)
+			}
+		}
+	case "W":
+		// clear all watched
+		count := len(m.watchedPIDs)
+		m.watchedPIDs = make(map[int]bool)
+		if count > 0 {
+			m.statusMessage = fmt.Sprintf("cleared %d watched processes", count)
+			m.statusExpiry = time.Now().Add(2 * time.Second)
+			return m, clearStatusAfter(2 * time.Second)
+		}
+
+	// kill process
+	case "K":
+		visible := m.visibleConnections()
+		if m.cursor < len(visible) {
+			conn := visible[m.cursor]
+			if conn.PID > 0 {
+				m.killTarget = &conn
+				m.showKillConfirm = true
+			}
+		}
 	}
 
 	return m, nil

internal/tui/messages.go

@@ -1,7 +1,9 @@
 package tui
 
 import (
+	"fmt"
 	"snitch/internal/collector"
+	"syscall"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
@@ -17,6 +19,15 @@ type errMsg struct {
 	err error
 }
 
+type killResultMsg struct {
+	pid     int
+	process string
+	success bool
+	err     error
+}
+
+type clearStatusMsg struct{}
+
 func (m model) tick() tea.Cmd {
 	return tea.Tick(m.interval, func(t time.Time) tea.Msg {
 		return tickMsg(t)
@@ -33,3 +44,40 @@ func (m model) fetchData() tea.Cmd {
 	}
 }
 
+func killProcess(pid int, process string) tea.Cmd {
+	return func() tea.Msg {
+		if pid <= 0 {
+			return killResultMsg{
+				pid:     pid,
+				process: process,
+				success: false,
+				err:     fmt.Errorf("invalid pid"),
+			}
+		}
+
+		// send SIGTERM first (graceful shutdown)
+		err := syscall.Kill(pid, syscall.SIGTERM)
+		if err != nil {
+			return killResultMsg{
+				pid:     pid,
+				process: process,
+				success: false,
+				err:     err,
+			}
+		}
+
+		return killResultMsg{
+			pid:     pid,
+			process: process,
+			success: true,
+			err:     nil,
+		}
+	}
+}
+
+func clearStatusAfter(d time.Duration) tea.Cmd {
+	return tea.Tick(d, func(t time.Time) tea.Msg {
+		return clearStatusMsg{}
+	})
+}
+

internal/tui/model.go

@@ -1,6 +1,7 @@
 package tui
 
 import (
+	"fmt"
 	"snitch/internal/collector"
 	"snitch/internal/theme"
 	"time"
@@ -35,6 +36,17 @@ type model struct {
 	interval    time.Duration
 	lastRefresh time.Time
 	err         error
+
+	// watched processes
+	watchedPIDs map[int]bool
+
+	// kill confirmation
+	showKillConfirm bool
+	killTarget      *collector.Connection
+
+	// status message (temporary feedback)
+	statusMessage string
+	statusExpiry  time.Time
 }
 
 type Options struct {
@@ -93,6 +105,7 @@ func New(opts Options) model {
 		theme:           theme.GetTheme(opts.Theme),
 		interval:        interval,
 		lastRefresh:     time.Now(),
+		watchedPIDs:     make(map[int]bool),
 	}
 }
 
@@ -127,6 +140,21 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case errMsg:
 		m.err = msg.err
 		return m, nil
+
+	case killResultMsg:
+		if msg.success {
+			m.statusMessage = fmt.Sprintf("killed %s (pid %d)", msg.process, msg.pid)
+		} else {
+			m.statusMessage = fmt.Sprintf("failed to kill pid %d: %v", msg.pid, msg.err)
+		}
+		m.statusExpiry = time.Now().Add(3 * time.Second)
+		return m, tea.Batch(m.fetchData(), clearStatusAfter(3*time.Second))
+
+	case clearStatusMsg:
+		if time.Now().After(m.statusExpiry) {
+			m.statusMessage = ""
+		}
+		return m, nil
 	}
 
 	return m, nil
@@ -142,7 +170,15 @@ func (m model) View() string {
 	if m.showDetail && m.selected != nil {
 		return m.renderDetail()
 	}
-	return m.renderMain()
+
+	main := m.renderMain()
+
+	// overlay kill confirmation modal on top of main view
+	if m.showKillConfirm && m.killTarget != nil {
+		return m.overlayModal(main, m.renderKillModal())
+	}
+
+	return main
 }
 
 func (m *model) applySorting() {
@@ -167,7 +203,8 @@ func (m *model) clampCursor() {
 }
 
 func (m model) visibleConnections() []collector.Connection {
-	var result []collector.Connection
+	var watched []collector.Connection
+	var unwatched []collector.Connection
 
 	for _, c := range m.connections {
 		if !m.matchesFilters(c) {
@@ -176,10 +213,15 @@ func (m model) visibleConnections() []collector.Connection {
 		if m.searchQuery != "" && !m.matchesSearch(c) {
 			continue
 		}
-		result = append(result, c)
+		if m.isWatched(c.PID) {
+			watched = append(watched, c)
+		} else {
+			unwatched = append(unwatched, c)
+		}
 	}
 
-	return result
+	// watched connections appear first
+	return append(watched, unwatched...)
 }
 
 func (m model) matchesFilters(c collector.Connection) bool {
@@ -218,3 +260,25 @@ func (m model) matchesSearch(c collector.Connection) bool {
 		containsIgnoreCase(c.Proto, m.searchQuery) ||
 		containsIgnoreCase(c.State, m.searchQuery)
 }
+
+func (m model) isWatched(pid int) bool {
+	if pid <= 0 {
+		return false
+	}
+	return m.watchedPIDs[pid]
+}
+
+func (m *model) toggleWatch(pid int) {
+	if pid <= 0 {
+		return
+	}
+	if m.watchedPIDs[pid] {
+		delete(m.watchedPIDs, pid)
+	} else {
+		m.watchedPIDs[pid] = true
+	}
+}
+
+func (m model) watchedCount() int {
+	return len(m.watchedPIDs)
+}

internal/tui/model_test.go

@@ -0,0 +1,303 @@
+package tui
+
+import (
+	"snitch/internal/collector"
+	"testing"
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/x/exp/teatest"
+)
+
+func TestTUI_InitialState(t *testing.T) {
+	m := New(Options{
+		Theme:    "dark",
+		Interval: time.Second,
+	})
+
+	if m.showTCP != true {
+		t.Error("expected showTCP to be true by default")
+	}
+	if m.showUDP != true {
+		t.Error("expected showUDP to be true by default")
+	}
+	if m.showListening != true {
+		t.Error("expected showListening to be true by default")
+	}
+	if m.showEstablished != true {
+		t.Error("expected showEstablished to be true by default")
+	}
+}
+
+func TestTUI_FilterOptions(t *testing.T) {
+	m := New(Options{
+		Theme:     "dark",
+		Interval:  time.Second,
+		TCP:       true,
+		UDP:       false,
+		FilterSet: true,
+	})
+
+	if m.showTCP != true {
+		t.Error("expected showTCP to be true")
+	}
+	if m.showUDP != false {
+		t.Error("expected showUDP to be false")
+	}
+}
+
+func TestTUI_MatchesFilters(t *testing.T) {
+	m := New(Options{
+		Theme:       "dark",
+		Interval:    time.Second,
+		TCP:         true,
+		UDP:         false,
+		Listening:   true,
+		Established: false,
+		FilterSet:   true,
+	})
+
+	tests := []struct {
+		name     string
+		conn     collector.Connection
+		expected bool
+	}{
+		{
+			name:     "tcp listen matches",
+			conn:     collector.Connection{Proto: "tcp", State: "LISTEN"},
+			expected: true,
+		},
+		{
+			name:     "tcp6 listen matches",
+			conn:     collector.Connection{Proto: "tcp6", State: "LISTEN"},
+			expected: true,
+		},
+		{
+			name:     "udp listen does not match",
+			conn:     collector.Connection{Proto: "udp", State: "LISTEN"},
+			expected: false,
+		},
+		{
+			name:     "tcp established does not match",
+			conn:     collector.Connection{Proto: "tcp", State: "ESTABLISHED"},
+			expected: false,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result := m.matchesFilters(tc.conn)
+			if result != tc.expected {
+				t.Errorf("matchesFilters() = %v, want %v", result, tc.expected)
+			}
+		})
+	}
+}
+
+func TestTUI_MatchesSearch(t *testing.T) {
+	m := New(Options{Theme: "dark"})
+	m.searchQuery = "firefox"
+
+	tests := []struct {
+		name     string
+		conn     collector.Connection
+		expected bool
+	}{
+		{
+			name:     "process name matches",
+			conn:     collector.Connection{Process: "firefox"},
+			expected: true,
+		},
+		{
+			name:     "process name case insensitive",
+			conn:     collector.Connection{Process: "Firefox"},
+			expected: true,
+		},
+		{
+			name:     "no match",
+			conn:     collector.Connection{Process: "chrome"},
+			expected: false,
+		},
+		{
+			name:     "matches in address",
+			conn:     collector.Connection{Raddr: "firefox.com"},
+			expected: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result := m.matchesSearch(tc.conn)
+			if result != tc.expected {
+				t.Errorf("matchesSearch() = %v, want %v", result, tc.expected)
+			}
+		})
+	}
+}
+
+func TestTUI_KeyBindings(t *testing.T) {
+	tm := teatest.NewTestModel(t, New(Options{Theme: "dark", Interval: time.Hour}))
+
+	// test quit with 'q'
+	tm.Send(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'q'}})
+
+	tm.WaitFinished(t, teatest.WithFinalTimeout(time.Second*3))
+}
+
+func TestTUI_ToggleFilters(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+
+	// initial state: all filters on
+	if m.showTCP != true || m.showUDP != true {
+		t.Fatal("expected all protocol filters on initially")
+	}
+
+	// toggle TCP with 't'
+	newModel, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'t'}})
+	m = newModel.(model)
+
+	if m.showTCP != false {
+		t.Error("expected showTCP to be false after toggle")
+	}
+
+	// toggle UDP with 'u'
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'u'}})
+	m = newModel.(model)
+
+	if m.showUDP != false {
+		t.Error("expected showUDP to be false after toggle")
+	}
+
+	// toggle listening with 'l'
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'l'}})
+	m = newModel.(model)
+
+	if m.showListening != false {
+		t.Error("expected showListening to be false after toggle")
+	}
+
+	// toggle established with 'e'
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'e'}})
+	m = newModel.(model)
+
+	if m.showEstablished != false {
+		t.Error("expected showEstablished to be false after toggle")
+	}
+}
+
+func TestTUI_HelpToggle(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+
+	if m.showHelp != false {
+		t.Fatal("expected showHelp to be false initially")
+	}
+
+	// toggle help with '?'
+	newModel, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'?'}})
+	m = newModel.(model)
+
+	if m.showHelp != true {
+		t.Error("expected showHelp to be true after toggle")
+	}
+
+	// toggle help off
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'?'}})
+	m = newModel.(model)
+
+	if m.showHelp != false {
+		t.Error("expected showHelp to be false after second toggle")
+	}
+}
+
+func TestTUI_CursorNavigation(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+
+	// add some test data
+	m.connections = []collector.Connection{
+		{PID: 1, Process: "proc1", Proto: "tcp", State: "LISTEN"},
+		{PID: 2, Process: "proc2", Proto: "tcp", State: "LISTEN"},
+		{PID: 3, Process: "proc3", Proto: "tcp", State: "LISTEN"},
+	}
+
+	if m.cursor != 0 {
+		t.Fatal("expected cursor at 0 initially")
+	}
+
+	// move down with 'j'
+	newModel, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'j'}})
+	m = newModel.(model)
+
+	if m.cursor != 1 {
+		t.Errorf("expected cursor at 1 after down, got %d", m.cursor)
+	}
+
+	// move down again
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'j'}})
+	m = newModel.(model)
+
+	if m.cursor != 2 {
+		t.Errorf("expected cursor at 2 after second down, got %d", m.cursor)
+	}
+
+	// move up with 'k'
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'k'}})
+	m = newModel.(model)
+
+	if m.cursor != 1 {
+		t.Errorf("expected cursor at 1 after up, got %d", m.cursor)
+	}
+
+	// go to top with 'g'
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'g'}})
+	m = newModel.(model)
+
+	if m.cursor != 0 {
+		t.Errorf("expected cursor at 0 after 'g', got %d", m.cursor)
+	}
+
+	// go to bottom with 'G'
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'G'}})
+	m = newModel.(model)
+
+	if m.cursor != 2 {
+		t.Errorf("expected cursor at 2 after 'G', got %d", m.cursor)
+	}
+}
+
+func TestTUI_WindowResize(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+
+	newModel, _ := m.Update(tea.WindowSizeMsg{Width: 120, Height: 40})
+	m = newModel.(model)
+
+	if m.width != 120 {
+		t.Errorf("expected width 120, got %d", m.width)
+	}
+	if m.height != 40 {
+		t.Errorf("expected height 40, got %d", m.height)
+	}
+}
+
+func TestTUI_ViewRenders(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+	m.width = 120
+	m.height = 40
+
+	m.connections = []collector.Connection{
+		{PID: 1234, Process: "nginx", Proto: "tcp", State: "LISTEN", Laddr: "0.0.0.0", Lport: 80},
+	}
+
+	// main view should render without panic
+	view := m.View()
+	if view == "" {
+		t.Error("expected non-empty view")
+	}
+
+	// help view
+	m.showHelp = true
+	helpView := m.View()
+	if helpView == "" {
+		t.Error("expected non-empty help view")
+	}
+}
+

internal/tui/symbols.go

@@ -0,0 +1,37 @@
+package tui
+
+// unicode symbols used throughout the TUI
+const (
+	// indicators
+	SymbolSelected   = string('\u25B8') // black right-pointing small triangle
+	SymbolWatched    = string('\u2605') // black star
+	SymbolWarning    = string('\u26A0') // warning sign
+	SymbolSuccess    = string('\u2713') // check mark
+	SymbolError      = string('\u2717') // ballot x
+	SymbolBullet     = string('\u2022') // bullet
+	SymbolArrowRight = string('\u2192') // rightwards arrow
+	SymbolArrowLeft  = string('\u2190') // leftwards arrow
+	SymbolArrowUp    = string('\u2191') // upwards arrow
+	SymbolArrowDown  = string('\u2193') // downwards arrow
+	SymbolRefresh    = string('\u21BB') // clockwise open circle arrow
+	SymbolEllipsis   = string('\u2026') // horizontal ellipsis
+
+	// box drawing rounded 
+	BoxTopLeft     = string('\u256D') // light arc down and right
+	BoxTopRight    = string('\u256E') // light arc down and left
+	BoxBottomLeft  = string('\u2570') // light arc up and right
+	BoxBottomRight = string('\u256F') // light arc up and left
+	BoxHorizontal  = string('\u2500') // light horizontal
+	BoxVertical    = string('\u2502') // light vertical
+
+	// box drawing connectors
+	BoxTeeDown  = string('\u252C') // light down and horizontal
+	BoxTeeUp    = string('\u2534') // light up and horizontal
+	BoxTeeRight = string('\u251C') // light vertical and right
+	BoxTeeLeft  = string('\u2524') // light vertical and left
+	BoxCross    = string('\u253C') // light vertical and horizontal
+
+	// misc
+	SymbolDash = string('\u2013') // en dash
+)
+

internal/tui/view.go

@@ -5,6 +5,8 @@ import (
 	"snitch/internal/collector"
 	"strings"
 	"time"
+
+	"github.com/mattn/go-runewidth"
 )
 
 func (m model) renderMain() string {
@@ -31,7 +33,7 @@ func (m model) renderTitle() string {
 	left := m.theme.Styles.Header.Render("snitch")
 
 	ago := time.Since(m.lastRefresh).Round(time.Millisecond * 100)
-	right := m.theme.Styles.Normal.Render(fmt.Sprintf("%d/%d connections  ↻ %s", len(visible), total, formatDuration(ago)))
+	right := m.theme.Styles.Normal.Render(fmt.Sprintf("%d/%d connections  %s %s", len(visible), total, SymbolRefresh, formatDuration(ago)))
 
 	w := m.safeWidth()
 	gap := w - len(stripAnsi(left)) - len(stripAnsi(right)) - 2
@@ -57,7 +59,7 @@ func (m model) renderFilters() string {
 		parts = append(parts, m.theme.Styles.Normal.Render("udp"))
 	}
 
-	parts = append(parts, m.theme.Styles.Border.Render("│"))
+	parts = append(parts, m.theme.Styles.Border.Render(BoxVertical))
 
 	if m.showListening {
 		parts = append(parts, m.theme.Styles.Success.Render("listen"))
@@ -80,9 +82,9 @@ func (m model) renderFilters() string {
 	left := "  " + strings.Join(parts, "  ")
 
 	sortLabel := sortFieldLabel(m.sortField)
-	sortDir := "↑"
+	sortDir := SymbolArrowUp
 	if m.sortReverse {
-		sortDir = "↓"
+		sortDir = SymbolArrowDown
 	}
 
 	var right string
@@ -122,7 +124,7 @@ func (m model) renderSeparator() string {
 	if w < 1 {
 		w = 76
 	}
-	line := "  " + strings.Repeat("─", w)
+	line := "  " + strings.Repeat(BoxHorizontal, w)
 	return m.theme.Styles.Border.Render(line) + "\n"
 }
 
@@ -157,19 +159,21 @@ func (m model) renderRow(c collector.Connection, selected bool) string {
 
 	indicator := "  "
 	if selected {
-		indicator = m.theme.Styles.Success.Render("▸ ")
+		indicator = m.theme.Styles.Success.Render(SymbolSelected + " ")
+	} else if m.isWatched(c.PID) {
+		indicator = m.theme.Styles.Watched.Render(SymbolWatched + " ")
 	}
 
 	process := truncate(c.Process, cols.process)
 	if process == "" {
-		process = "–"
+		process = SymbolDash
 	}
 
 	port := fmt.Sprintf("%d", c.Lport)
 	proto := c.Proto
 	state := c.State
 	if state == "" {
-		state = "–"
+		state = SymbolDash
 	}
 
 	local := c.Laddr
@@ -200,7 +204,18 @@ func (m model) renderRow(c collector.Connection, selected bool) string {
 }
 
 func (m model) renderStatusLine() string {
-	left := "  " + m.theme.Styles.Normal.Render("t/u proto  l/e/o state  s sort  / search  ? help  q quit")
+	// show status message if present
+	if m.statusMessage != "" {
+		return "  " + m.theme.Styles.Warning.Render(m.statusMessage)
+	}
+
+	left := "  " + m.theme.Styles.Normal.Render("t/u proto  l/e/o state  w watch  K kill  s sort  / search  ? help  q quit")
+
+	// show watched count if any
+	if m.watchedCount() > 0 {
+		watchedInfo := fmt.Sprintf("  watching: %d", m.watchedCount())
+		left += m.theme.Styles.Watched.Render(watchedInfo)
+	}
 
 	return left
 }
@@ -233,6 +248,12 @@ func (m model) renderHelp() string {
   s            cycle sort field
   S            reverse sort order
 
+  process management
+  ──────────────────
+  w            watch/unwatch process (highlight & track)
+  W            clear all watched processes
+  K            kill process (with confirmation)
+
   other
   ─────
   /            search
@@ -254,7 +275,7 @@ func (m model) renderDetail() string {
 
 	b.WriteString("\n")
 	b.WriteString("  " + m.theme.Styles.Header.Render("connection details") + "\n")
-	b.WriteString("  " + m.theme.Styles.Border.Render(strings.Repeat("─", 40)) + "\n\n")
+	b.WriteString("  " + m.theme.Styles.Border.Render(strings.Repeat(BoxHorizontal, 40)) + "\n\n")
 
 	fields := []struct {
 		label string
@@ -274,7 +295,7 @@ func (m model) renderDetail() string {
 	for _, f := range fields {
 		val := f.value
 		if val == "" || val == "0" || val == ":0" {
-			val = "–"
+			val = SymbolDash
 		}
 		line := fmt.Sprintf("  %-12s  %s\n", m.theme.Styles.Header.Render(f.label), val)
 		b.WriteString(line)
@@ -286,6 +307,179 @@ func (m model) renderDetail() string {
 	return b.String()
 }
 
+func (m model) renderKillModal() string {
+	if m.killTarget == nil {
+		return ""
+	}
+
+	c := m.killTarget
+	processName := c.Process
+	if processName == "" {
+		processName = "(unknown)"
+	}
+
+	// count how many connections this process has
+	connCount := 0
+	for _, conn := range m.connections {
+		if conn.PID == c.PID {
+			connCount++
+		}
+	}
+
+	// build modal content
+	var lines []string
+	lines = append(lines, "")
+	lines = append(lines, m.theme.Styles.Error.Render("  "+SymbolWarning+"  KILL PROCESS?  "))
+	lines = append(lines, "")
+	lines = append(lines, fmt.Sprintf("  process:  %s", m.theme.Styles.Header.Render(processName)))
+	lines = append(lines, fmt.Sprintf("  pid:      %s", m.theme.Styles.Header.Render(fmt.Sprintf("%d", c.PID))))
+	lines = append(lines, fmt.Sprintf("  user:     %s", c.User))
+	lines = append(lines, fmt.Sprintf("  conns:    %d", connCount))
+	lines = append(lines, "")
+	lines = append(lines, m.theme.Styles.Warning.Render("  sends SIGTERM to process"))
+	if connCount > 1 {
+		lines = append(lines, m.theme.Styles.Warning.Render(fmt.Sprintf("  will close all %d connections", connCount)))
+	}
+	lines = append(lines, "")
+	lines = append(lines, fmt.Sprintf("  %s confirm   %s cancel",
+		m.theme.Styles.Success.Render("[y]"),
+		m.theme.Styles.Error.Render("[n]")))
+	lines = append(lines, "")
+
+	return strings.Join(lines, "\n")
+}
+
+func (m model) overlayModal(background, modal string) string {
+	bgLines := strings.Split(background, "\n")
+	modalLines := strings.Split(modal, "\n")
+
+	// find max modal line width using runewidth for proper unicode handling
+	modalWidth := 0
+	for _, line := range modalLines {
+		w := stringWidth(line)
+		if w > modalWidth {
+			modalWidth = w
+		}
+	}
+	modalWidth += 4 // padding for box
+
+	modalHeight := len(modalLines)
+	boxWidth := modalWidth + 2 // include border chars │ │
+
+	// calculate modal position (centered)
+	startRow := (m.height - modalHeight) / 2
+	if startRow < 2 {
+		startRow = 2
+	}
+	startCol := (m.width - boxWidth) / 2
+	if startCol < 0 {
+		startCol = 0
+	}
+
+	// build result
+	result := make([]string, len(bgLines))
+	copy(result, bgLines)
+
+	// ensure we have enough lines
+	for len(result) < startRow+modalHeight+2 {
+		result = append(result, strings.Repeat(" ", m.width))
+	}
+
+	// helper to build a line with modal overlay
+	buildLine := func(bgLine, modalContent string) string {
+		modalVisibleWidth := stringWidth(modalContent)
+		endCol := startCol + modalVisibleWidth
+
+		leftBg := visibleSubstring(bgLine, 0, startCol)
+		rightBg := visibleSubstring(bgLine, endCol, m.width)
+
+		// pad left side if needed
+		leftLen := stringWidth(leftBg)
+		if leftLen < startCol {
+			leftBg = leftBg + strings.Repeat(" ", startCol-leftLen)
+		}
+
+		return leftBg + modalContent + rightBg
+	}
+
+	// draw top border
+	borderRow := startRow - 1
+	if borderRow >= 0 && borderRow < len(result) {
+		border := m.theme.Styles.Border.Render(BoxTopLeft + strings.Repeat(BoxHorizontal, modalWidth) + BoxTopRight)
+		result[borderRow] = buildLine(result[borderRow], border)
+	}
+
+	// draw modal content with side borders
+	for i, line := range modalLines {
+		row := startRow + i
+		if row >= 0 && row < len(result) {
+			content := line
+			padding := modalWidth - stringWidth(line)
+			if padding > 0 {
+				content = line + strings.Repeat(" ", padding)
+			}
+			boxedLine := m.theme.Styles.Border.Render(BoxVertical) + content + m.theme.Styles.Border.Render(BoxVertical)
+			result[row] = buildLine(result[row], boxedLine)
+		}
+	}
+
+	// draw bottom border
+	bottomRow := startRow + modalHeight
+	if bottomRow >= 0 && bottomRow < len(result) {
+		border := m.theme.Styles.Border.Render(BoxBottomLeft + strings.Repeat(BoxHorizontal, modalWidth) + BoxBottomRight)
+		result[bottomRow] = buildLine(result[bottomRow], border)
+	}
+
+	return strings.Join(result, "\n")
+}
+
+// stringWidth returns the display width of a string excluding ANSI codes
+func stringWidth(s string) int {
+	return runewidth.StringWidth(stripAnsi(s))
+}
+
+// visibleSubstring extracts a substring by visible column positions, preserving ANSI codes
+func visibleSubstring(s string, start, end int) string {
+	if start >= end {
+		return ""
+	}
+
+	var result strings.Builder
+	visiblePos := 0
+	inEscape := false
+
+	for _, r := range s {
+		// detect start of ANSI escape sequence
+		if r == '\x1b' {
+			inEscape = true
+			result.WriteRune(r)
+			continue
+		}
+
+		if inEscape {
+			result.WriteRune(r)
+			// end of escape sequence is a letter
+			if (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') {
+				inEscape = false
+			}
+			continue
+		}
+
+		// regular visible character
+		w := runewidth.RuneWidth(r)
+		if visiblePos >= start && visiblePos+w <= end {
+			result.WriteRune(r)
+		}
+		visiblePos += w
+
+		if visiblePos >= end {
+			break
+		}
+	}
+
+	return result.String()
+}
+
 func (m model) scrollOffset(pageSize, total int) int {
 	if total <= pageSize {
 		return 0