Merge pull request #6 from karol-broda/feat/reverse-dns-lookup

- Switch to nixos-25.11 for modern apple-sdk packages
- Use apple-sdk_15 which includes SecTrustCopyCertificateChain (macOS 12+)
- Required for Go 1.25 crypto/x509 compatibility on darwin

.github/workflows/ci.yaml

@@ -36,3 +36,21 @@ jobs:
         with:
           version: latest
 
+  nix-build:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-14]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: DeterminateSystems/nix-installer-action@v17
+
+      - uses: DeterminateSystems/magic-nix-cache-action@v9
+
+      - name: nix flake check
+        run: nix flake check
+
+      - name: nix build
+        run: nix build
+

.github/workflows/release.yaml

@@ -27,6 +27,7 @@ jobs:
           args: release --clean
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          AUR_KEY: ${{ secrets.AUR_KEY }}
 
   release-darwin:
     needs: release-linux

.goreleaser-darwin.yaml

@@ -25,6 +25,9 @@ archives:
       {{- .Version }}_
       {{- .Os }}_
       {{- .Arch }}
+    files:
+      - LICENSE
+      - README.md
 
 release:
   github:

.goreleaser.yaml

@@ -33,6 +33,9 @@ archives:
       {{- .Os }}_
       {{- .Arch }}
       {{- if .Arm }}v{{ .Arm }}{{ end }}
+    files:
+      - LICENSE
+      - README.md
 
 checksum:
   name_template: "checksums.txt"
@@ -61,6 +64,27 @@ 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

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

@@ -2,6 +2,8 @@
 
 a friendlier `ss` / `netstat` for humans. inspect network connections with a clean tui or styled tables.
 
+![snitch demo](demo/demo.gif)
+
 ## install
 
 ### go
@@ -26,18 +28,48 @@ nix profile install 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
+```
+
+### shell script
+
+```bash
+curl -sSL https://raw.githubusercontent.com/karol-broda/snitch/master/install.sh | sh
+```
+
+installs to `~/.local/bin` if available, otherwise `/usr/local/bin`. override with:
+
+```bash
+curl -sSL https://raw.githubusercontent.com/karol-broda/snitch/master/install.sh | INSTALL_DIR=~/bin sh
+```
+
+> **macos:** the install script automatically removes the quarantine attribute (`com.apple.quarantine`) from the binary to allow it to run without gatekeeper warnings. to disable this, set `KEEP_QUARANTINE=1`.
+
 ### binary
 
 download from [releases](https://github.com/karol-broda/snitch/releases):
 
-```bash
-# amd64
-curl -L https://github.com/karol-broda/snitch/releases/latest/download/snitch_linux_amd64.tar.gz | tar xz
-sudo mv snitch /usr/local/bin/
+- **linux:** `snitch_<version>_linux_<arch>.tar.gz` or `.deb`/`.rpm`/`.apk`
+- **macos:** `snitch_<version>_darwin_<arch>.tar.gz`
 
-# or install .deb/.rpm/.apk from releases
+```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
@@ -71,6 +103,9 @@ 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
@@ -111,6 +146,16 @@ snitch watch -i 1s | jq '.count'
 snitch watch -l -i 500ms
 ```
 
+### `snitch upgrade`
+
+check for updates and upgrade in-place.
+
+```bash
+snitch upgrade              # check for updates
+snitch upgrade --yes        # upgrade automatically
+snitch upgrade -v 0.1.7     # install specific version
+```
+
 ## filters
 
 shortcut flags work on all commands:
@@ -169,5 +214,6 @@ theme = "auto"
 
 ## requirements
 
-- linux (reads from `/proc/net/*`)
-- root or `CAP_NET_ADMIN` for full process info
+- linux or macos
+- 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

@@ -6,7 +6,7 @@ import (
 	"strings"
 	"testing"
 
-	"snitch/internal/testutil"
+	"github.com/karol-broda/snitch/internal/testutil"
 )
 
 // TestCLIContract tests the CLI interface contracts as specified in the README
@@ -71,7 +71,7 @@ func TestCLIContract(t *testing.T) {
 			name:           "version",
 			args:           []string{"version"},
 			expectExitCode: 0,
-			expectStdout:   []string{"snitch", "commit:", "built:"},
+			expectStdout:   []string{"snitch", "commit", "built"},
 			expectStderr:   nil,
 			description:    "version command should show version information",
 		},
@@ -361,10 +361,11 @@ func resetGlobalFlags() {
 	showTimestamp = false
 	sortBy = ""
 	fields = ""
-	ipv4 = false
-	ipv6 = false
+	filterIPv4 = false
+	filterIPv6 = false
 	colorMode = "auto"
-	numeric = false
+	resolveAddrs = true
+	resolvePorts = false
 }
 
 // TestEnvironmentVariables tests that environment variables are properly handled

cmd/golden_test.go

@@ -9,8 +9,8 @@ import (
 	"strings"
 	"testing"
 
-	"snitch/internal/collector"
-	"snitch/internal/testutil"
+	"github.com/karol-broda/snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/testutil"
 )
 
 var updateGolden = flag.Bool("update-golden", false, "Update golden files")

cmd/json.go

@@ -15,4 +15,5 @@ var jsonCmd = &cobra.Command{
 
 func init() {
 	rootCmd.AddCommand(jsonCmd)
+	addFilterFlags(jsonCmd)
 }

cmd/ls.go

@@ -8,10 +8,10 @@ import (
 	"log"
 	"os"
 	"os/exec"
-	"snitch/internal/collector"
-	"snitch/internal/color"
-	"snitch/internal/config"
-	"snitch/internal/resolver"
+	"github.com/karol-broda/snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/color"
+	"github.com/karol-broda/snitch/internal/config"
+	"github.com/karol-broda/snitch/internal/resolver"
 	"strconv"
 	"strings"
 	"text/tabwriter"
@@ -22,20 +22,16 @@ 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
+	resolveAddrs  bool
+	resolvePorts  bool
 	plainOutput   bool
 )
 
@@ -56,39 +52,16 @@ Available filters:
 }
 
 func runListCommand(outputFormat string, args []string) {
-	color.Init(colorMode)
-
-	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()
+	rt, err := NewRuntime(args, colorMode)
 	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
-		collector.SortConnections(filteredConnections, collector.SortOptions{
+		rt.SortConnections(collector.SortOptions{
 			Field:     collector.SortByLport,
 			Direction: collector.SortAsc,
 		})
@@ -99,93 +72,26 @@ 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
@@ -193,14 +99,18 @@ func getFieldMap(c collector.Connection) map[string]string {
 	lport := strconv.Itoa(c.Lport)
 	rport := strconv.Itoa(c.Rport)
 	
-	// Apply name resolution if not in numeric mode
-	if !numeric {
+	// apply address resolution
+	if resolveAddrs {
 		if resolvedLaddr := resolver.ResolveAddr(c.Laddr); resolvedLaddr != c.Laddr {
 			laddr = resolvedLaddr
 		}
 		if resolvedRaddr := resolver.ResolveAddr(c.Raddr); resolvedRaddr != c.Raddr && c.Raddr != "*" && c.Raddr != "" {
 			raddr = resolvedRaddr
 		}
+	}
+
+	// apply port resolution
+	if resolvePorts {
 		if resolvedLport := resolver.ResolvePort(c.Lport, c.Proto); resolvedLport != strconv.Itoa(c.Lport) {
 			lport = resolvedLport
 		}
@@ -483,20 +393,17 @@ 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().BoolVar(&resolveAddrs, "resolve-addrs", !cfg.Defaults.Numeric, "Resolve IP addresses to hostnames")
+	lsCmd.Flags().BoolVar(&resolvePorts, "resolve-ports", false, "Resolve port numbers to service names")
 	lsCmd.Flags().BoolVarP(&plainOutput, "plain", "p", false, "Plain output (parsable, no styling)")
+
+	// shared filter flags
+	addFilterFlags(lsCmd)
 }

cmd/ls_test.go

@@ -4,8 +4,8 @@ import (
 	"strings"
 	"testing"
 
-	"snitch/internal/collector"
-	"snitch/internal/testutil"
+	"github.com/karol-broda/snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/testutil"
 )
 
 func TestLsCommand_EmptyResults(t *testing.T) {
@@ -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

@@ -3,7 +3,7 @@ package cmd
 import (
 	"fmt"
 	"os"
-	"snitch/internal/config"
+	"github.com/karol-broda/snitch/internal/config"
 
 	"github.com/spf13/cobra"
 )
@@ -40,12 +40,13 @@ 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")
-	rootCmd.Flags().BoolVarP(&topListen, "listen", "l", false, "Show only listening sockets")
-	rootCmd.Flags().BoolVarP(&topEstab, "established", "e", false, "Show only established connections")
+	rootCmd.Flags().BoolVar(&topResolveAddrs, "resolve-addrs", !cfg.Defaults.Numeric, "Resolve IP addresses to hostnames")
+	rootCmd.Flags().BoolVar(&topResolvePorts, "resolve-ports", false, "Resolve port numbers to service names")
+
+	// shared filter flags for root command
+	addFilterFlags(rootCmd)
 }

cmd/runtime.go

@@ -0,0 +1,203 @@
+package cmd
+
+import (
+	"fmt"
+	"github.com/karol-broda/snitch/internal/collector"
+	"github.com/karol-broda/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
+	ResolveAddrs bool
+	ResolvePorts 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) (*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,
+		ResolveAddrs: resolveAddrs,
+		ResolvePorts: resolvePorts,
+	}, 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

@@ -8,7 +8,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
-	"snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/collector"
 	"sort"
 	"strconv"
 	"strings"
@@ -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

@@ -2,21 +2,20 @@ package cmd
 
 import (
 	"log"
-	"snitch/internal/config"
-	"snitch/internal/tui"
+	"github.com/karol-broda/snitch/internal/config"
+	"github.com/karol-broda/snitch/internal/tui"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/spf13/cobra"
 )
 
+// top-specific flags
 var (
-	topTheme    string
-	topInterval time.Duration
-	topTCP      bool
-	topUDP      bool
-	topListen   bool
-	topEstab    bool
+	topTheme        string
+	topInterval     time.Duration
+	topResolveAddrs bool
+	topResolvePorts bool
 )
 
 var topCmd = &cobra.Command{
@@ -31,16 +30,18 @@ var topCmd = &cobra.Command{
 		}
 
 		opts := tui.Options{
-			Theme:    theme,
-			Interval: topInterval,
+			Theme:        theme,
+			Interval:     topInterval,
+			ResolveAddrs: topResolveAddrs,
+			ResolvePorts: topResolvePorts,
 		}
 
 		// if any filter flag is set, use exclusive mode
-		if topTCP || topUDP || topListen || topEstab {
-			opts.TCP = topTCP
-			opts.UDP = topUDP
-			opts.Listening = topListen
-			opts.Established = topEstab
+		if filterTCP || filterUDP || filterListen || filterEstab {
+			opts.TCP = filterTCP
+			opts.UDP = filterUDP
+			opts.Listening = filterListen
+			opts.Established = filterEstab
 			opts.Other = false
 			opts.FilterSet = true
 		}
@@ -57,10 +58,13 @@ 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")
-	topCmd.Flags().BoolVarP(&topListen, "listen", "l", false, "Show only listening sockets")
-	topCmd.Flags().BoolVarP(&topEstab, "established", "e", false, "Show only established connections")
+	topCmd.Flags().BoolVar(&topResolveAddrs, "resolve-addrs", !cfg.Defaults.Numeric, "Resolve IP addresses to hostnames")
+	topCmd.Flags().BoolVar(&topResolvePorts, "resolve-ports", false, "Resolve port numbers to service names")
+
+	// shared filter flags
+	addFilterFlags(topCmd)
 }

cmd/trace.go

@@ -7,8 +7,8 @@ import (
 	"log"
 	"os"
 	"os/signal"
-	"snitch/internal/collector"
-	"snitch/internal/resolver"
+	"github.com/karol-broda/snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/resolver"
 	"strings"
 	"syscall"
 	"time"
@@ -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/upgrade.go

@@ -0,0 +1,688 @@
+package cmd
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strconv"
+	"strings"
+
+	"github.com/fatih/color"
+	"github.com/spf13/cobra"
+
+	"github.com/karol-broda/snitch/internal/tui"
+)
+
+const (
+	repoOwner = "karol-broda"
+	repoName  = "snitch"
+	githubAPI = "https://api.github.com"
+	firstUpgradeVersion = "0.1.8"
+)
+
+var (
+	upgradeYes     bool
+	upgradeVersion string
+)
+
+var upgradeCmd = &cobra.Command{
+	Use:   "upgrade",
+	Short: "Check for updates and optionally upgrade snitch",
+	Long: `Check for available updates and show upgrade instructions.
+
+Use --yes to perform an in-place upgrade automatically.
+Use --version to install a specific version.`,
+	RunE: runUpgrade,
+}
+
+func init() {
+	upgradeCmd.Flags().BoolVarP(&upgradeYes, "yes", "y", false, "Perform the upgrade automatically")
+	upgradeCmd.Flags().StringVarP(&upgradeVersion, "version", "v", "", "Install a specific version (e.g., v0.1.7)")
+	rootCmd.AddCommand(upgradeCmd)
+}
+
+type githubRelease struct {
+	TagName string `json:"tag_name"`
+	HTMLURL string `json:"html_url"`
+}
+
+type githubCommit struct {
+	SHA string `json:"sha"`
+}
+
+type githubCompare struct {
+	Status      string `json:"status"`
+	AheadBy     int    `json:"ahead_by"`
+	BehindBy    int    `json:"behind_by"`
+	TotalCommits int   `json:"total_commits"`
+}
+
+func runUpgrade(cmd *cobra.Command, args []string) error {
+	current := Version
+	nixInstall := isNixInstall()
+	nixVersion := isNixVersion(current)
+
+	if upgradeVersion != "" {
+		if nixInstall || nixVersion {
+			return handleNixSpecificVersion(current, upgradeVersion)
+		}
+		return handleSpecificVersion(current, upgradeVersion)
+	}
+
+	latest, err := fetchLatestVersion()
+	if err != nil {
+		return fmt.Errorf("failed to check for updates: %w", err)
+	}
+
+	if nixInstall || nixVersion {
+		return handleNixUpgrade(current, latest)
+	}
+
+	currentClean := strings.TrimPrefix(current, "v")
+	latestClean := strings.TrimPrefix(latest, "v")
+
+	printVersionComparison(current, latest)
+
+	if currentClean == latestClean {
+		green := color.New(color.FgGreen)
+		green.Println(tui.SymbolSuccess + " you are running the latest version")
+		return nil
+	}
+
+	if current == "dev" {
+		yellow := color.New(color.FgYellow)
+		yellow.Println(tui.SymbolWarning + " you are running a development build")
+		fmt.Println()
+		fmt.Println("use one of the methods below to install a release version:")
+		fmt.Println()
+		printUpgradeInstructions()
+		return nil
+	}
+
+	green := color.New(color.FgGreen, color.Bold)
+	green.Printf(tui.SymbolSuccess+" update available: %s "+tui.SymbolArrowRight+" %s\n", current, latest)
+	fmt.Println()
+
+	if !upgradeYes {
+		printUpgradeInstructions()
+		fmt.Println()
+		faint := color.New(color.Faint)
+		cmdStyle := color.New(color.FgCyan)
+		faint.Print("  in-place      ")
+		cmdStyle.Println("snitch upgrade --yes")
+		return nil
+	}
+
+	return performUpgrade(latest)
+}
+
+func handleSpecificVersion(current, target string) error {
+	if !strings.HasPrefix(target, "v") {
+		target = "v" + target
+	}
+	targetClean := strings.TrimPrefix(target, "v")
+
+	printVersionComparisonTarget(current, target)
+
+	if isVersionLower(targetClean, firstUpgradeVersion) {
+		yellow := color.New(color.FgYellow)
+		yellow.Printf(tui.SymbolWarning+" warning: the upgrade command was introduced in v%s\n", firstUpgradeVersion)
+		faint := color.New(color.Faint)
+		faint.Printf("  version %s does not include this command\n", target)
+		faint.Println("  you will need to use other methods to upgrade from that version")
+		fmt.Println()
+	}
+
+	currentClean := strings.TrimPrefix(current, "v")
+	if currentClean == targetClean {
+		green := color.New(color.FgGreen)
+		green.Println(tui.SymbolSuccess + " you are already running this version")
+		return nil
+	}
+
+	if !upgradeYes {
+		faint := color.New(color.Faint)
+		cmdStyle := color.New(color.FgCyan)
+		if isVersionLower(targetClean, currentClean) {
+			yellow := color.New(color.FgYellow)
+			yellow.Printf(tui.SymbolArrowDown+" this will downgrade from %s to %s\n", current, target)
+		} else {
+			green := color.New(color.FgGreen)
+			green.Printf(tui.SymbolArrowUp+" this will upgrade from %s to %s\n", current, target)
+		}
+		fmt.Println()
+		faint.Print("run ")
+		cmdStyle.Printf("snitch upgrade --version %s --yes", target)
+		faint.Println(" to proceed")
+		return nil
+	}
+
+	return performUpgrade(target)
+}
+
+func handleNixUpgrade(current, latest string) error {
+	faint := color.New(color.Faint)
+	version := color.New(color.FgCyan)
+
+	currentCommit := extractCommitFromVersion(current)
+	dirty := isNixDirty(current)
+
+	faint.Print("current  ")
+	version.Print(current)
+	if currentCommit != "" {
+		faint.Printf(" (commit %s)", currentCommit)
+	}
+	fmt.Println()
+
+	faint.Print("latest   ")
+	version.Println(latest)
+	fmt.Println()
+
+	if dirty {
+		yellow := color.New(color.FgYellow)
+		yellow.Println(tui.SymbolWarning + " you are running a dirty nix build (uncommitted changes)")
+		fmt.Println()
+		printNixUpgradeInstructions()
+		return nil
+	}
+
+	if currentCommit == "" {
+		yellow := color.New(color.FgYellow)
+		yellow.Println(tui.SymbolWarning + " this is a nix installation")
+		faint.Println("  nix store is immutable; use nix commands to upgrade")
+		fmt.Println()
+		printNixUpgradeInstructions()
+		return nil
+	}
+
+	releaseCommit, err := fetchCommitForTag(latest)
+	if err != nil {
+		faint.Printf("  (could not fetch release commit: %v)\n", err)
+		fmt.Println()
+		yellow := color.New(color.FgYellow)
+		yellow.Println(tui.SymbolWarning + " this is a nix installation")
+		faint.Println("  nix store is immutable; use nix commands to upgrade")
+		fmt.Println()
+		printNixUpgradeInstructions()
+		return nil
+	}
+
+	releaseShort := releaseCommit
+	if len(releaseShort) > 7 {
+		releaseShort = releaseShort[:7]
+	}
+
+	if strings.HasPrefix(releaseCommit, currentCommit) || strings.HasPrefix(currentCommit, releaseShort) {
+		green := color.New(color.FgGreen)
+		green.Printf(tui.SymbolSuccess+" you are running %s (commit %s)\n", latest, releaseShort)
+		return nil
+	}
+
+	comparison, err := compareCommits(latest, currentCommit)
+	if err != nil {
+		green := color.New(color.FgGreen, color.Bold)
+		green.Printf(tui.SymbolSuccess+" update available: %s "+tui.SymbolArrowRight+" %s\n", currentCommit, latest)
+		faint.Printf("  your commit: %s\n", currentCommit)
+		faint.Printf("  release:     %s (%s)\n", releaseShort, latest)
+		fmt.Println()
+		yellow := color.New(color.FgYellow)
+		yellow.Println(tui.SymbolWarning + " this is a nix installation")
+		faint.Println("  nix store is immutable; use nix commands to upgrade")
+		fmt.Println()
+		printNixUpgradeInstructions()
+		return nil
+	}
+
+	if comparison.AheadBy > 0 {
+		cyan := color.New(color.FgCyan)
+		cyan.Printf(tui.SymbolArrowUp+" you are %d commit(s) ahead of %s\n", comparison.AheadBy, latest)
+		faint.Printf("  your commit: %s\n", currentCommit)
+		faint.Printf("  release:     %s (%s)\n", releaseShort, latest)
+		fmt.Println()
+		faint.Println("you are running a newer build than the latest release")
+		return nil
+	}
+
+	if comparison.BehindBy > 0 {
+		green := color.New(color.FgGreen, color.Bold)
+		green.Printf(tui.SymbolSuccess+" update available: %d commit(s) behind %s\n", comparison.BehindBy, latest)
+		faint.Printf("  your commit: %s\n", currentCommit)
+		faint.Printf("  release:     %s (%s)\n", releaseShort, latest)
+		fmt.Println()
+		yellow := color.New(color.FgYellow)
+		yellow.Println(tui.SymbolWarning + " this is a nix installation")
+		faint.Println("  nix store is immutable; use nix commands to upgrade")
+		fmt.Println()
+		printNixUpgradeInstructions()
+		return nil
+	}
+
+	green := color.New(color.FgGreen)
+	green.Printf(tui.SymbolSuccess+" you are running %s (commit %s)\n", latest, releaseShort)
+	return nil
+}
+
+func handleNixSpecificVersion(current, target string) error {
+	if !strings.HasPrefix(target, "v") {
+		target = "v" + target
+	}
+
+	printVersionComparisonTarget(current, target)
+
+	yellow := color.New(color.FgYellow)
+	yellow.Println(tui.SymbolWarning + " this is a nix installation")
+	faint := color.New(color.Faint)
+	faint.Println("  nix store is immutable; in-place upgrades are not supported")
+	fmt.Println()
+
+	bold := color.New(color.Bold)
+	cmd := color.New(color.FgCyan)
+
+	bold.Println("to install a specific version with nix:")
+	fmt.Println()
+
+	faint.Print("  specific ref    ")
+	cmd.Printf("nix profile install github:%s/%s/%s\n", repoOwner, repoName, target)
+
+	faint.Print("  latest          ")
+	cmd.Printf("nix profile install github:%s/%s\n", repoOwner, repoName)
+
+	return nil
+}
+
+func isVersionLower(v1, v2 string) bool {
+	parts1 := parseVersion(v1)
+	parts2 := parseVersion(v2)
+
+	for i := 0; i < 3; i++ {
+		if parts1[i] < parts2[i] {
+			return true
+		}
+		if parts1[i] > parts2[i] {
+			return false
+		}
+	}
+	return false
+}
+
+func parseVersion(v string) [3]int {
+	var parts [3]int
+	segments := strings.Split(v, ".")
+
+	for i := 0; i < len(segments) && i < 3; i++ {
+		n, err := strconv.Atoi(segments[i])
+		if err == nil {
+			parts[i] = n
+		}
+	}
+	return parts
+}
+
+func fetchLatestVersion() (string, error) {
+	url := fmt.Sprintf("%s/repos/%s/%s/releases/latest", githubAPI, repoOwner, repoName)
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("github api returned status %d", resp.StatusCode)
+	}
+
+	var release githubRelease
+	if err := json.NewDecoder(resp.Body).Decode(&release); err != nil {
+		return "", err
+	}
+
+	if release.TagName == "" {
+		return "", fmt.Errorf("no releases found")
+	}
+
+	return release.TagName, nil
+}
+
+func printVersionComparison(current, latest string) {
+	faint := color.New(color.Faint)
+	version := color.New(color.FgCyan)
+
+	faint.Print("current  ")
+	version.Println(current)
+	faint.Print("latest   ")
+	version.Println(latest)
+	fmt.Println()
+}
+
+func printVersionComparisonTarget(current, target string) {
+	faint := color.New(color.Faint)
+	version := color.New(color.FgCyan)
+
+	faint.Print("current  ")
+	version.Println(current)
+	faint.Print("target   ")
+	version.Println(target)
+	fmt.Println()
+}
+
+func printUpgradeInstructions() {
+	bold := color.New(color.Bold)
+	faint := color.New(color.Faint)
+	cmd := color.New(color.FgCyan)
+
+	bold.Println("upgrade options:")
+	fmt.Println()
+
+	faint.Print("  go install    ")
+	cmd.Printf("go install github.com/%s/%s@latest\n", repoOwner, repoName)
+
+	faint.Print("  shell script  ")
+	cmd.Printf("curl -sSL https://raw.githubusercontent.com/%s/%s/master/install.sh | sh\n", repoOwner, repoName)
+
+	faint.Print("  arch (aur)    ")
+	cmd.Println("yay -S snitch-bin")
+
+	faint.Print("  nix           ")
+	cmd.Printf("nix profile upgrade --inputs-from github:%s/%s\n", repoOwner, repoName)
+}
+
+func performUpgrade(version string) error {
+	execPath, err := os.Executable()
+	if err != nil {
+		return fmt.Errorf("failed to get executable path: %w", err)
+	}
+
+	execPath, err = filepath.EvalSymlinks(execPath)
+	if err != nil {
+		return fmt.Errorf("failed to resolve executable path: %w", err)
+	}
+
+	if strings.HasPrefix(execPath, "/nix/store/") {
+		yellow := color.New(color.FgYellow)
+		yellow.Println(tui.SymbolWarning + " cannot perform in-place upgrade for nix installation")
+		fmt.Println()
+		printNixUpgradeInstructions()
+		return nil
+	}
+
+	goos := runtime.GOOS
+	goarch := runtime.GOARCH
+
+	versionClean := strings.TrimPrefix(version, "v")
+	archiveName := fmt.Sprintf("%s_%s_%s_%s.tar.gz", repoName, versionClean, goos, goarch)
+	downloadURL := fmt.Sprintf("https://github.com/%s/%s/releases/download/%s/%s",
+		repoOwner, repoName, version, archiveName)
+
+	faint := color.New(color.Faint)
+	cyan := color.New(color.FgCyan)
+	faint.Print(tui.SymbolDownload + " downloading ")
+	cyan.Printf("%s", archiveName)
+	faint.Println("...")
+
+	resp, err := http.Get(downloadURL)
+	if err != nil {
+		return fmt.Errorf("failed to download: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("download failed with status %d", resp.StatusCode)
+	}
+
+	tmpDir, err := os.MkdirTemp("", "snitch-upgrade-*")
+	if err != nil {
+		return fmt.Errorf("failed to create temp directory: %w", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	binaryPath, err := extractBinaryFromTarGz(resp.Body, tmpDir)
+	if err != nil {
+		return fmt.Errorf("failed to extract binary: %w", err)
+	}
+
+	if goos == "darwin" {
+		removeQuarantine(binaryPath)
+	}
+
+	// check if we can write to the target location
+	targetDir := filepath.Dir(execPath)
+	if !isWritable(targetDir) {
+		yellow := color.New(color.FgYellow)
+		cmdStyle := color.New(color.FgCyan)
+
+		yellow.Printf(tui.SymbolWarning+" elevated permissions required to install to %s\n", targetDir)
+		fmt.Println()
+		faint.Println("run with sudo or install to a user-writable location:")
+		fmt.Println()
+		faint.Print("  sudo         ")
+		cmdStyle.Println("sudo snitch upgrade --yes")
+		faint.Print("  custom dir   ")
+		cmdStyle.Printf("curl -sSL https://raw.githubusercontent.com/%s/%s/master/install.sh | INSTALL_DIR=~/.local/bin sh\n",
+			repoOwner, repoName)
+		return nil
+	}
+
+	// replace the binary
+	backupPath := execPath + ".bak"
+	if err := os.Rename(execPath, backupPath); err != nil {
+		return fmt.Errorf("failed to backup current binary: %w", err)
+	}
+
+	if err := copyFile(binaryPath, execPath); err != nil {
+		// try to restore backup
+		if restoreErr := os.Rename(backupPath, execPath); restoreErr != nil {
+			return fmt.Errorf("failed to install new binary and restore backup: %w (restore error: %v)", err, restoreErr)
+		}
+		return fmt.Errorf("failed to install new binary: %w", err)
+	}
+
+	if err := os.Chmod(execPath, 0755); err != nil {
+		return fmt.Errorf("failed to set executable permissions: %w", err)
+	}
+
+	if err := os.Remove(backupPath); err != nil {
+		// non-fatal, just warn
+		yellow := color.New(color.FgYellow)
+		yellow.Fprintf(os.Stderr, tui.SymbolWarning + " warning: failed to remove backup file %s: %v\n", backupPath, err)
+	}
+
+	green := color.New(color.FgGreen, color.Bold)
+	green.Printf(tui.SymbolSuccess + " successfully upgraded to %s\n", version)
+	return nil
+}
+
+func extractBinaryFromTarGz(r io.Reader, destDir string) (string, error) {
+	gzr, err := gzip.NewReader(r)
+	if err != nil {
+		return "", err
+	}
+	defer gzr.Close()
+
+	tr := tar.NewReader(gzr)
+
+	for {
+		header, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return "", err
+		}
+
+		if header.Typeflag != tar.TypeReg {
+			continue
+		}
+
+		// look for the snitch binary
+		name := filepath.Base(header.Name)
+		if name != repoName {
+			continue
+		}
+
+		destPath := filepath.Join(destDir, name)
+		outFile, err := os.Create(destPath)
+		if err != nil {
+			return "", err
+		}
+
+		if _, err := io.Copy(outFile, tr); err != nil {
+			outFile.Close()
+			return "", err
+		}
+		outFile.Close()
+
+		return destPath, nil
+	}
+
+	return "", fmt.Errorf("binary not found in archive")
+}
+
+func isWritable(path string) bool {
+	testFile := filepath.Join(path, ".snitch-write-test")
+	f, err := os.Create(testFile)
+	if err != nil {
+		return false
+	}
+	f.Close()
+	os.Remove(testFile)
+	return true
+}
+
+func copyFile(src, dst string) error {
+	srcFile, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer srcFile.Close()
+
+	dstFile, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer dstFile.Close()
+
+	if _, err := io.Copy(dstFile, srcFile); err != nil {
+		return err
+	}
+
+	return dstFile.Sync()
+}
+
+func removeQuarantine(path string) {
+	cmd := exec.Command("xattr", "-d", "com.apple.quarantine", path)
+	if err := cmd.Run(); err == nil {
+		faint := color.New(color.Faint)
+		faint.Println("  removed macOS quarantine attribute")
+	}
+}
+
+func isNixInstall() bool {
+	execPath, err := os.Executable()
+	if err != nil {
+		return false
+	}
+
+	resolved, err := filepath.EvalSymlinks(execPath)
+	if err != nil {
+		return false
+	}
+
+	return strings.HasPrefix(resolved, "/nix/store/")
+}
+
+var nixVersionPattern = regexp.MustCompile(`^nix-([a-f0-9]+)(-dirty)?$`)
+var commitHashPattern = regexp.MustCompile(`^[a-f0-9]{7,40}$`)
+
+func isNixVersion(version string) bool {
+	if nixVersionPattern.MatchString(version) {
+		return true
+	}
+	if commitHashPattern.MatchString(version) {
+		return true
+	}
+	return false
+}
+
+func extractCommitFromVersion(version string) string {
+	matches := nixVersionPattern.FindStringSubmatch(version)
+	if len(matches) >= 2 {
+		return matches[1]
+	}
+	if commitHashPattern.MatchString(version) {
+		return version
+	}
+	return ""
+}
+
+func isNixDirty(version string) bool {
+	return strings.HasSuffix(version, "-dirty")
+}
+
+func fetchCommitForTag(tag string) (string, error) {
+	url := fmt.Sprintf("%s/repos/%s/%s/commits/%s", githubAPI, repoOwner, repoName, tag)
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("github api returned status %d", resp.StatusCode)
+	}
+
+	var commit githubCommit
+	if err := json.NewDecoder(resp.Body).Decode(&commit); err != nil {
+		return "", err
+	}
+
+	return commit.SHA, nil
+}
+
+func compareCommits(base, head string) (*githubCompare, error) {
+	url := fmt.Sprintf("%s/repos/%s/%s/compare/%s...%s", githubAPI, repoOwner, repoName, base, head)
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("github api returned status %d", resp.StatusCode)
+	}
+
+	var compare githubCompare
+	if err := json.NewDecoder(resp.Body).Decode(&compare); err != nil {
+		return nil, err
+	}
+
+	return &compare, nil
+}
+
+func printNixUpgradeInstructions() {
+	bold := color.New(color.Bold)
+	faint := color.New(color.Faint)
+	cmd := color.New(color.FgCyan)
+
+	bold.Println("nix upgrade options:")
+	fmt.Println()
+
+	faint.Print("  flake profile   ")
+	cmd.Printf("nix profile install github:%s/%s\n", repoOwner, repoName)
+
+	faint.Print("  flake update    ")
+	cmd.Println("nix flake update snitch  (in your system/home-manager config)")
+
+	faint.Print("  rebuild         ")
+	cmd.Println("nixos-rebuild switch  or  home-manager switch")
+}
+

cmd/version.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"runtime"
 
+	"github.com/fatih/color"
 	"github.com/spf13/cobra"
 )
 
@@ -17,11 +18,25 @@ var versionCmd = &cobra.Command{
 	Use:   "version",
 	Short: "Show version/build info",
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Printf("snitch %s\n", Version)
-		fmt.Printf("  commit: %s\n", Commit)
-		fmt.Printf("  built:  %s\n", Date)
-		fmt.Printf("  go:     %s\n", runtime.Version())
-		fmt.Printf("  os:     %s/%s\n", runtime.GOOS, runtime.GOARCH)
+		bold := color.New(color.Bold)
+		cyan := color.New(color.FgCyan)
+		faint := color.New(color.Faint)
+
+		bold.Print("snitch ")
+		cyan.Println(Version)
+		fmt.Println()
+
+		faint.Print("  commit  ")
+		fmt.Println(Commit)
+
+		faint.Print("  built   ")
+		fmt.Println(Date)
+
+		faint.Print("  go      ")
+		fmt.Println(runtime.Version())
+
+		faint.Print("  os      ")
+		fmt.Printf("%s/%s\n", runtime.GOOS, runtime.GOARCH)
 	},
 }
 

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,
-				"count":       len(filteredConnections),
+				"connections": connections,
+				"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

@@ -2,39 +2,23 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1765687488,
-        "narHash": "sha256-7YAJ6xgBAQ/Nr+7MI13Tui1ULflgAdKh63m1tfYV7+M=",
+        "lastModified": 1766201043,
+        "narHash": "sha256-eplAP+rorKKd0gNjV3rA6+0WMzb1X1i16F5m5pASnjA=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "d02bcc33948ca19b0aaa0213fe987ceec1f4ebe1",
+        "rev": "b3aad468604d3e488d627c0b43984eb60e75e782",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixos-25.05",
+        "ref": "nixos-25.11",
         "repo": "nixpkgs",
         "type": "github"
       }
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs",
-        "systems": "systems"
-      }
-    },
-    "systems": {
-      "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
-        "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-systems",
-        "repo": "default",
-        "type": "github"
+        "nixpkgs": "nixpkgs"
       }
     }
   },

flake.nix

@@ -1,103 +1,110 @@
 {
   description = "snitch - a friendlier ss/netstat for humans";
 
-  inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
-    systems.url = "github:nix-systems/default";
-  };
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
 
-  outputs = { self, nixpkgs, systems }:
+  outputs = { self, nixpkgs }:
     let
-      supportedSystems = import systems;
-      forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: f system);
+      systems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+      eachSystem = nixpkgs.lib.genAttrs systems;
 
-      # go 1.25 overlay (required until nixpkgs has it)
-      goOverlay = final: prev:
+      # go 1.25 binary derivation (required until nixpkgs ships it)
+      mkGo125 = pkgs:
         let
           version = "1.25.0";
-          platformInfo = {
-            "x86_64-linux" = { suffix = "linux-amd64"; sri = "sha256-KFKvDLIKExObNEiZLmm4aOUO0Pih5ZQO4d6eGaEjthM="; };
-            "aarch64-linux" = { suffix = "linux-arm64"; sri = "sha256-Bd511plKJ4NpmBXuVTvVqTJ9i3mZHeNuOLZoYngvVK4="; };
-            "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: ${hostSystem}");
+          platform = {
+            "x86_64-linux" = { suffix = "linux-amd64"; hash = "sha256-KFKvDLIKExObNEiZLmm4aOUO0Pih5ZQO4d6eGaEjthM="; GOOS = "linux"; GOARCH = "amd64"; };
+            "aarch64-linux" = { suffix = "linux-arm64"; hash = "sha256-Bd511plKJ4NpmBXuVTvVqTJ9i3mZHeNuOLZoYngvVK4="; GOOS = "linux"; GOARCH = "arm64"; };
+            "x86_64-darwin" = { suffix = "darwin-amd64"; hash = "sha256-W9YOgjA3BiwjB8cegRGAmGURZxTW9rQQWXz1B139gO8="; GOOS = "darwin"; GOARCH = "amd64"; };
+            "aarch64-darwin" = { suffix = "darwin-arm64"; hash = "sha256-VEkyhEFW2Bcveij3fyrJwVojBGaYtiQ/YzsKCwDAdJw="; GOOS = "darwin"; GOARCH = "arm64"; };
+          }.${pkgs.stdenv.hostPlatform.system} or (throw "unsupported system: ${pkgs.stdenv.hostPlatform.system}");
         in
-        {
-          go_1_25 = prev.stdenvNoCC.mkDerivation {
-            pname = "go";
-            inherit version;
-            src = prev.fetchurl {
-              url = "https://go.dev/dl/go${version}.${chosen.suffix}.tar.gz";
-              hash = chosen.sri;
-            };
-            dontBuild = true;
-            installPhase = ''
-              runHook preInstall
-              mkdir -p "$out"/{bin,share}
-              tar -C "$TMPDIR" -xzf "$src"
-              cp -a "$TMPDIR/go" "$out/share/go"
-              ln -s "$out/share/go/bin/go" "$out/bin/go"
-              ln -s "$out/share/go/bin/gofmt" "$out/bin/gofmt"
-              runHook postInstall
-            '';
-            dontPatchELF = true;
-            dontStrip = true;
+        pkgs.stdenv.mkDerivation {
+          pname = "go";
+          inherit version;
+          src = pkgs.fetchurl {
+            url = "https://go.dev/dl/go${version}.${platform.suffix}.tar.gz";
+            inherit (platform) hash;
+          };
+          dontBuild = true;
+          dontPatchELF = true;
+          dontStrip = true;
+          installPhase = ''
+            runHook preInstall
+            mkdir -p $out/{bin,share/go}
+            tar -xzf $src --strip-components=1 -C $out/share/go
+            ln -s $out/share/go/bin/go $out/bin/go
+            ln -s $out/share/go/bin/gofmt $out/bin/gofmt
+            runHook postInstall
+          '';
+          passthru = {
+            inherit (platform) GOOS GOARCH;
+          };
+        };
+
+      pkgsFor = system: import nixpkgs { inherit system; };
+
+      mkSnitch = pkgs:
+        let
+          rev = self.shortRev or self.dirtyShortRev or "unknown";
+          version = "nix-${rev}";
+          isDarwin = pkgs.stdenv.isDarwin;
+          go = mkGo125 pkgs;
+          buildGoModule = pkgs.buildGoModule.override { inherit go; };
+        in
+        buildGoModule {
+          pname = "snitch";
+          inherit version;
+          src = self;
+          vendorHash = "sha256-fX3wOqeOgjH7AuWGxPQxJ+wbhp240CW8tiF4rVUUDzk=";
+          # darwin requires cgo for libproc, linux uses pure go with /proc
+          env.CGO_ENABLED = if isDarwin then "1" else "0";
+          env.GOTOOLCHAIN = "local";
+          # darwin: use macOS 15 SDK for SecTrustCopyCertificateChain (Go 1.25 crypto/x509)
+          buildInputs = pkgs.lib.optionals isDarwin [ pkgs.apple-sdk_15 ];
+          ldflags = [
+            "-s"
+            "-w"
+            "-X snitch/cmd.Version=${version}"
+            "-X snitch/cmd.Commit=${rev}"
+            "-X snitch/cmd.Date=${self.lastModifiedDate or "unknown"}"
+          ];
+          meta = {
+            description = "a friendlier ss/netstat for humans";
+            homepage = "https://github.com/karol-broda/snitch";
+            license = pkgs.lib.licenses.mit;
+            platforms = pkgs.lib.platforms.linux ++ pkgs.lib.platforms.darwin;
+            mainProgram = "snitch";
           };
         };
     in
     {
-      overlays.default = final: prev: {
-        snitch = final.callPackage ./nix/package.nix { };
-      };
-
-      packages = forAllSystems (system:
-        let
-          pkgs = import nixpkgs {
-            inherit system;
-            overlays = [ goOverlay ];
-          };
-        in
+      packages = eachSystem (system:
+        let pkgs = pkgsFor system; in
         {
-          default = pkgs.buildGoModule {
-            pname = "snitch";
-            version = self.shortRev or self.dirtyShortRev or "dev";
-            src = self;
-            vendorHash = "sha256-BNNbA72puV0QSLkAlgn/buJJt7mIlVkbTEBhTXOg8pY=";
-            env.CGO_ENABLED = 0;
-            ldflags = [
-              "-s" "-w"
-              "-X snitch/cmd.version=${self.shortRev or "dev"}"
-              "-X snitch/cmd.commit=${self.shortRev 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";
-            };
-          };
+          default = mkSnitch pkgs;
+          snitch = mkSnitch pkgs;
         }
       );
 
-      devShells = forAllSystems (system:
+      devShells = eachSystem (system:
         let
-          pkgs = import nixpkgs {
-            inherit system;
-            overlays = [ goOverlay ];
-          };
+          pkgs = pkgsFor system;
+          go = mkGo125 pkgs;
         in
         {
           default = pkgs.mkShell {
-            packages = [ pkgs.go_1_25 pkgs.git ];
-            GOTOOLCHAIN = "local";
+            packages = [ go pkgs.git pkgs.vhs ];
+            env.GOTOOLCHAIN = "local";
             shellHook = ''
               echo "go toolchain: $(go version)"
             '';
           };
         }
       );
+
+      overlays.default = final: _prev: {
+        snitch = mkSnitch final;
+      };
     };
 }

go.mod

@@ -1,4 +1,4 @@
-module snitch
+module github.com/karol-broda/snitch
 
 go 1.24.0
 
@@ -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/sync v0.15.0 // indirect
+	golang.org/x/exp v0.0.0-20231006140011-7918f672742d // 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=

install.sh

@@ -0,0 +1,113 @@
+#!/bin/sh
+set -e
+
+REPO="karol-broda/snitch"
+BINARY_NAME="snitch"
+
+# allow override via environment
+INSTALL_DIR="${INSTALL_DIR:-}"
+KEEP_QUARANTINE="${KEEP_QUARANTINE:-}"
+
+detect_install_dir() {
+    if [ -n "$INSTALL_DIR" ]; then
+        echo "$INSTALL_DIR"
+        return
+    fi
+
+    # prefer user-local directory if it exists and is in PATH
+    if [ -d "$HOME/.local/bin" ] && echo "$PATH" | grep -q "$HOME/.local/bin"; then
+        echo "$HOME/.local/bin"
+        return
+    fi
+
+    # fallback to /usr/local/bin
+    echo "/usr/local/bin"
+}
+
+detect_os() {
+    os=$(uname -s | tr '[:upper:]' '[:lower:]')
+    case "$os" in
+        darwin) echo "darwin" ;;
+        linux) echo "linux" ;;
+        *)
+            echo "error: unsupported operating system: $os" >&2
+            exit 1
+            ;;
+    esac
+}
+
+detect_arch() {
+    arch=$(uname -m)
+    case "$arch" in
+        x86_64|amd64) echo "amd64" ;;
+        aarch64|arm64) echo "arm64" ;;
+        armv7l) echo "armv7" ;;
+        *)
+            echo "error: unsupported architecture: $arch" >&2
+            exit 1
+            ;;
+    esac
+}
+
+fetch_latest_version() {
+    version=$(curl -sL "https://api.github.com/repos/${REPO}/releases/latest" | grep '"tag_name"' | head -1 | cut -d'"' -f4)
+    if [ -z "$version" ]; then
+        echo "error: failed to fetch latest version" >&2
+        exit 1
+    fi
+    echo "$version"
+}
+
+main() {
+    os=$(detect_os)
+    arch=$(detect_arch)
+    install_dir=$(detect_install_dir)
+    version=$(fetch_latest_version)
+    version_no_v="${version#v}"
+
+    archive_name="${BINARY_NAME}_${version_no_v}_${os}_${arch}.tar.gz"
+    download_url="https://github.com/${REPO}/releases/download/${version}/${archive_name}"
+
+    echo "installing ${BINARY_NAME} ${version} for ${os}/${arch}..."
+
+    tmp_dir=$(mktemp -d)
+    trap 'rm -rf "$tmp_dir"' EXIT
+
+    echo "downloading ${download_url}..."
+    if ! curl -sL --fail "$download_url" -o "${tmp_dir}/${archive_name}"; then
+        echo "error: failed to download ${download_url}" >&2
+        exit 1
+    fi
+
+    echo "extracting..."
+    tar -xzf "${tmp_dir}/${archive_name}" -C "$tmp_dir"
+
+    if [ ! -f "${tmp_dir}/${BINARY_NAME}" ]; then
+        echo "error: binary not found in archive" >&2
+        exit 1
+    fi
+
+    # remove macos quarantine attribute unless disabled
+    if [ "$os" = "darwin" ] && [ -z "$KEEP_QUARANTINE" ]; then
+        if xattr -d com.apple.quarantine "${tmp_dir}/${BINARY_NAME}" 2>/dev/null; then
+            echo "warning: removed macOS quarantine attribute from binary"
+        fi
+    fi
+
+    # install binary
+    if [ -w "$install_dir" ]; then
+        mv "${tmp_dir}/${BINARY_NAME}" "${install_dir}/${BINARY_NAME}"
+    else
+        echo "elevated permissions required to install to ${install_dir}"
+        sudo mv "${tmp_dir}/${BINARY_NAME}" "${install_dir}/${BINARY_NAME}"
+    fi
+
+    chmod +x "${install_dir}/${BINARY_NAME}"
+
+    echo "installed ${BINARY_NAME} to ${install_dir}/${BINARY_NAME}"
+    echo ""
+    echo "run '${BINARY_NAME} --help' to get started"
+}
+
+main
+

internal/collector/collector_darwin.go

@@ -246,11 +246,6 @@ func getSocketInfo(pid, fd int, procName string, uid int, user string) (Connecti
 		raddr = ipv6ToString(info.raddr6)
 	}
 
-	state := ""
-	if info.sock_type == C.SOCK_STREAM {
-		state = tcpStateToString(int(info.state))
-	}
-
 	if laddr == "0.0.0.0" || laddr == "::" {
 		laddr = "*"
 	}
@@ -258,6 +253,18 @@ func getSocketInfo(pid, fd int, procName string, uid int, user string) (Connecti
 		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,

internal/collector/collector_linux.go

@@ -226,6 +226,13 @@ func parseProcNet(path, proto string, ipVersion int, inodeMap map[int64]*process
 
 		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,
@@ -277,13 +284,22 @@ func parseState(hexState, proto string) string {
 		if s, exists := tcpStates[state]; exists {
 			return s
 		}
-	} else {
-		if state == 0x07 {
-			return "CLOSE"
-		}
 		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 ""
 }
 

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,
-		"SYN_SENT":    2,
-		"SYN_RECV":    3,
-		"FIN_WAIT1":   4,
-		"FIN_WAIT2":   5,
-		"TIME_WAIT":   6,
-		"CLOSE_WAIT":  7,
-		"LAST_ACK":    8,
-		"CLOSING":     9,
-		"CLOSED":      10,
+		"UNCONNECTED": 1, // udp sockets bound but not connected to a specific peer
+		"ESTABLISHED": 2,
+		"SYN_SENT":    3,
+		"SYN_RECV":    4,
+		"FIN_WAIT1":   5,
+		"FIN_WAIT2":   6,
+		"TIME_WAIT":   7,
+		"CLOSE_WAIT":  8,
+		"LAST_ACK":    9,
+		"CLOSING":     10,
+		"CLOSED":      11,
 	}
 
 	if o, exists := order[strings.ToUpper(state)]; exists {

internal/testutil/testutil.go

@@ -5,7 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/collector"
 )
 
 // TestCollector wraps MockCollector for use in tests

internal/tui/helpers.go

@@ -1,9 +1,8 @@
 package tui
 
 import (
-	"fmt"
 	"regexp"
-	"snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/collector"
 	"strings"
 )
 
@@ -14,7 +13,7 @@ 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`)
@@ -44,10 +43,3 @@ func sortFieldLabel(f collector.SortField) string {
 	}
 }
 
-func formatRemote(addr string, port int) string {
-	if addr == "" || addr == "*" || port == 0 {
-		return "-"
-	}
-	return fmt.Sprintf("%s:%d", addr, port)
-}
-

internal/tui/keys.go

@@ -1,7 +1,9 @@
 package tui
 
 import (
-	"snitch/internal/collector"
+	"fmt"
+	"github.com/karol-broda/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 +161,77 @@ 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
+			}
+		}
+
+	// toggle address resolution
+	case "n":
+		m.resolveAddrs = !m.resolveAddrs
+		if m.resolveAddrs {
+			m.statusMessage = "address resolution: on"
+		} else {
+			m.statusMessage = "address resolution: off"
+		}
+		m.statusExpiry = time.Now().Add(2 * time.Second)
+		return m, clearStatusAfter(2 * time.Second)
+
+	// toggle port resolution
+	case "N":
+		m.resolvePorts = !m.resolvePorts
+		if m.resolvePorts {
+			m.statusMessage = "port resolution: on"
+		} else {
+			m.statusMessage = "port resolution: off"
+		}
+		m.statusExpiry = time.Now().Add(2 * time.Second)
+		return m, clearStatusAfter(2 * time.Second)
 	}
 
 	return m, nil

internal/tui/messages.go

@@ -1,7 +1,9 @@
 package tui
 
 import (
-	"snitch/internal/collector"
+	"fmt"
+	"github.com/karol-broda/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

@@ -1,8 +1,9 @@
 package tui
 
 import (
-	"snitch/internal/collector"
-	"snitch/internal/theme"
+	"fmt"
+	"github.com/karol-broda/snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/theme"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
@@ -27,6 +28,10 @@ type model struct {
 	sortField   collector.SortField
 	sortReverse bool
 
+	// display options
+	resolveAddrs bool // when true, resolve IP addresses to hostnames
+	resolvePorts bool // when true, resolve port numbers to service names
+
 	// ui state
 	theme       *theme.Theme
 	showHelp    bool
@@ -35,17 +40,30 @@ 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 {
-	Theme       string
-	Interval    time.Duration
-	TCP         bool
-	UDP         bool
-	Listening   bool
-	Established bool
-	Other       bool
-	FilterSet   bool // true if user specified any filter flags
+	Theme        string
+	Interval     time.Duration
+	TCP          bool
+	UDP          bool
+	Listening    bool
+	Established  bool
+	Other        bool
+	FilterSet    bool // true if user specified any filter flags
+	ResolveAddrs bool // when true, resolve IP addresses to hostnames
+	ResolvePorts bool // when true, resolve port numbers to service names
 }
 
 func New(opts Options) model {
@@ -90,9 +108,12 @@ func New(opts Options) model {
 		showEstablished: showEstablished,
 		showOther:       showOther,
 		sortField:       collector.SortByLport,
+		resolveAddrs:    opts.ResolveAddrs,
+		resolvePorts:    opts.ResolvePorts,
 		theme:           theme.GetTheme(opts.Theme),
 		interval:        interval,
 		lastRefresh:     time.Now(),
+		watchedPIDs:     make(map[int]bool),
 	}
 }
 
@@ -127,6 +148,21 @@ 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 +178,15 @@ 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 +211,8 @@ 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 +221,15 @@ 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 +268,25 @@ 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 +1,432 @@
+package tui
+
+import (
+	"github.com/karol-broda/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")
+	}
+}
+
+func TestTUI_ResolutionOptions(t *testing.T) {
+	// test default resolution settings
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+
+	if m.resolveAddrs != false {
+		t.Error("expected resolveAddrs to be false by default (must be explicitly set)")
+	}
+	if m.resolvePorts != false {
+		t.Error("expected resolvePorts to be false by default")
+	}
+
+	// test with explicit options
+	m2 := New(Options{
+		Theme:        "dark",
+		Interval:     time.Hour,
+		ResolveAddrs: true,
+		ResolvePorts: true,
+	})
+
+	if m2.resolveAddrs != true {
+		t.Error("expected resolveAddrs to be true when set")
+	}
+	if m2.resolvePorts != true {
+		t.Error("expected resolvePorts to be true when set")
+	}
+}
+
+func TestTUI_ToggleResolution(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour, ResolveAddrs: true})
+
+	if m.resolveAddrs != true {
+		t.Fatal("expected resolveAddrs to be true initially")
+	}
+
+	// toggle address resolution with 'n'
+	newModel, _ := m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'n'}})
+	m = newModel.(model)
+
+	if m.resolveAddrs != false {
+		t.Error("expected resolveAddrs to be false after toggle")
+	}
+
+	// toggle back
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'n'}})
+	m = newModel.(model)
+
+	if m.resolveAddrs != true {
+		t.Error("expected resolveAddrs to be true after second toggle")
+	}
+
+	// toggle port resolution with 'N'
+	if m.resolvePorts != false {
+		t.Fatal("expected resolvePorts to be false initially")
+	}
+
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'N'}})
+	m = newModel.(model)
+
+	if m.resolvePorts != true {
+		t.Error("expected resolvePorts to be true after toggle")
+	}
+
+	// toggle back
+	newModel, _ = m.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'N'}})
+	m = newModel.(model)
+
+	if m.resolvePorts != false {
+		t.Error("expected resolvePorts to be false after second toggle")
+	}
+}
+
+func TestTUI_ResolveAddrHelper(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+	m.resolveAddrs = false
+
+	// when resolution is off, should return original address
+	addr := m.resolveAddr("192.168.1.1")
+	if addr != "192.168.1.1" {
+		t.Errorf("expected original address when resolution off, got %s", addr)
+	}
+
+	// empty and wildcard addresses should pass through unchanged
+	if m.resolveAddr("") != "" {
+		t.Error("expected empty string to pass through")
+	}
+	if m.resolveAddr("*") != "*" {
+		t.Error("expected wildcard to pass through")
+	}
+}
+
+func TestTUI_ResolvePortHelper(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+	m.resolvePorts = false
+
+	// when resolution is off, should return port number as string
+	port := m.resolvePort(80, "tcp")
+	if port != "80" {
+		t.Errorf("expected '80' when resolution off, got %s", port)
+	}
+
+	port = m.resolvePort(443, "tcp")
+	if port != "443" {
+		t.Errorf("expected '443' when resolution off, got %s", port)
+	}
+}
+
+func TestTUI_FormatRemoteHelper(t *testing.T) {
+	m := New(Options{Theme: "dark", Interval: time.Hour})
+	m.resolveAddrs = false
+	m.resolvePorts = false
+
+	// empty/wildcard addresses should return dash
+	if m.formatRemote("", 80, "tcp") != "-" {
+		t.Error("expected dash for empty address")
+	}
+	if m.formatRemote("*", 80, "tcp") != "-" {
+		t.Error("expected dash for wildcard address")
+	}
+	if m.formatRemote("192.168.1.1", 0, "tcp") != "-" {
+		t.Error("expected dash for zero port")
+	}
+
+	// valid address:port should format correctly
+	result := m.formatRemote("192.168.1.1", 443, "tcp")
+	if result != "192.168.1.1:443" {
+		t.Errorf("expected '192.168.1.1:443', got %s", result)
+	}
+}
+

internal/tui/symbols.go

@@ -0,0 +1,38 @@
+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
+	SymbolDownload   = string('\u21E9') // downwards white arrow
+
+	// 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

@@ -2,9 +2,13 @@ package tui
 
 import (
 	"fmt"
-	"snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/collector"
+	"github.com/karol-broda/snitch/internal/resolver"
+	"strconv"
 	"strings"
 	"time"
+
+	"github.com/mattn/go-runewidth"
 )
 
 func (m model) renderMain() string {
@@ -31,7 +35,7 @@ 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
@@ -45,44 +49,21 @@ func (m model) renderTitle() string {
 func (m model) renderFilters() string {
 	var parts []string
 
-	if m.showTCP {
-		parts = append(parts, m.theme.Styles.Success.Render("tcp"))
-	} else {
-		parts = append(parts, m.theme.Styles.Normal.Render("tcp"))
-	}
+	parts = append(parts, m.renderFilterLabel("t", "cp", m.showTCP))
+	parts = append(parts, m.renderFilterLabel("u", "dp", m.showUDP))
 
-	if m.showUDP {
-		parts = append(parts, m.theme.Styles.Success.Render("udp"))
-	} else {
-		parts = append(parts, m.theme.Styles.Normal.Render("udp"))
-	}
+	parts = append(parts, m.theme.Styles.Border.Render(BoxVertical))
 
-	parts = append(parts, m.theme.Styles.Border.Render("│"))
-
-	if m.showListening {
-		parts = append(parts, m.theme.Styles.Success.Render("listen"))
-	} else {
-		parts = append(parts, m.theme.Styles.Normal.Render("listen"))
-	}
-
-	if m.showEstablished {
-		parts = append(parts, m.theme.Styles.Success.Render("estab"))
-	} else {
-		parts = append(parts, m.theme.Styles.Normal.Render("estab"))
-	}
-
-	if m.showOther {
-		parts = append(parts, m.theme.Styles.Success.Render("other"))
-	} else {
-		parts = append(parts, m.theme.Styles.Normal.Render("other"))
-	}
+	parts = append(parts, m.renderFilterLabel("l", "isten", m.showListening))
+	parts = append(parts, m.renderFilterLabel("e", "stab", m.showEstablished))
+	parts = append(parts, m.renderFilterLabel("o", "ther", m.showOther))
 
 	left := "  " + strings.Join(parts, "  ")
 
 	sortLabel := sortFieldLabel(m.sortField)
-	sortDir := "↑"
+	sortDir := SymbolArrowUp
 	if m.sortReverse {
-		sortDir = "↓"
+		sortDir = SymbolArrowDown
 	}
 
 	var right string
@@ -117,12 +98,24 @@ func (m model) renderTableHeader() string {
 	return m.theme.Styles.Header.Render(header) + "\n"
 }
 
+func (m model) renderFilterLabel(firstChar, rest string, active bool) string {
+	baseStyle := m.theme.Styles.Normal
+	if active {
+		baseStyle = m.theme.Styles.Success
+	}
+
+	underlinedFirst := baseStyle.Underline(true).Render(firstChar)
+	restPart := baseStyle.Render(rest)
+
+	return underlinedFirst + restPart
+}
+
 func (m model) renderSeparator() string {
 	w := m.width - 4
 	if w < 1 {
 		w = 76
 	}
-	line := "  " + strings.Repeat("─", w)
+	line := "  " + strings.Repeat(BoxHorizontal, w)
 	return m.theme.Styles.Border.Render(line) + "\n"
 }
 
@@ -132,8 +125,11 @@ func (m model) renderConnections() string {
 	pageSize := m.pageSize()
 
 	if len(visible) == 0 {
-		empty := "\n  " + m.theme.Styles.Normal.Render("no connections match filters") + "\n"
-		return empty
+		b.WriteString("  " + m.theme.Styles.Normal.Render("no connections match filters") + "\n")
+		for i := 1; i < pageSize; i++ {
+			b.WriteString("\n")
+		}
+		return b.String()
 	}
 
 	start := m.scrollOffset(pageSize, len(visible))
@@ -157,27 +153,29 @@ 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)
+	port := truncate(m.resolvePort(c.Lport, c.Proto), cols.port)
 	proto := c.Proto
 	state := c.State
 	if state == "" {
-		state = "–"
+		state = SymbolDash
 	}
 
-	local := c.Laddr
+	local := truncate(m.resolveAddr(c.Laddr), cols.local)
 	if local == "*" || local == "" {
 		local = "*"
 	}
 
-	remote := formatRemote(c.Raddr, c.Rport)
+	remote := truncate(m.formatRemote(c.Raddr, c.Rport, c.Proto), cols.remote)
 
 	// apply styling
 	protoStyled := m.theme.Styles.GetProtoStyle(proto).Render(fmt.Sprintf("%-*s", cols.proto, proto))
@@ -189,8 +187,8 @@ func (m model) renderRow(c collector.Connection, selected bool) string {
 		cols.port, port,
 		protoStyled,
 		stateStyled,
-		cols.local, truncate(local, cols.local),
-		truncate(remote, cols.remote))
+		cols.local, local,
+		remote)
 
 	if selected {
 		return m.theme.Styles.Selected.Render(row) + "\n"
@@ -200,7 +198,33 @@ 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  n/N dns  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)
+	}
+
+	// show dns resolution status
+	var resolveStatus string
+	if m.resolveAddrs && m.resolvePorts {
+		resolveStatus = "all"
+	} else if m.resolveAddrs {
+		resolveStatus = "addrs"
+	} else if m.resolvePorts {
+		resolveStatus = "ports"
+	} else {
+		resolveStatus = "off"
+	}
+	if resolveStatus != "addrs" { // addrs is the default, don't show
+		left += m.theme.Styles.Normal.Render(fmt.Sprintf("  dns: %s", resolveStatus))
+	}
 
 	return left
 }
@@ -233,6 +257,17 @@ func (m model) renderHelp() string {
   s            cycle sort field
   S            reverse sort order
 
+  display
+  ───────
+  n            toggle address resolution (dns)
+  N            toggle port resolution (service names)
+
+  process management
+  ──────────────────
+  w            watch/unwatch process (highlight & track)
+  W            clear all watched processes
+  K            kill process (with confirmation)
+
   other
   ─────
   /            search
@@ -254,7 +289,12 @@ 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")
+
+	localAddr := m.resolveAddr(c.Laddr)
+	localPort := m.resolvePort(c.Lport, c.Proto)
+	remoteAddr := m.resolveAddr(c.Raddr)
+	remotePort := m.resolvePort(c.Rport, c.Proto)
 
 	fields := []struct {
 		label string
@@ -265,8 +305,8 @@ func (m model) renderDetail() string {
 		{"user", c.User},
 		{"protocol", c.Proto},
 		{"state", c.State},
-		{"local", fmt.Sprintf("%s:%d", c.Laddr, c.Lport)},
-		{"remote", fmt.Sprintf("%s:%d", c.Raddr, c.Rport)},
+		{"local", fmt.Sprintf("%s:%s", localAddr, localPort)},
+		{"remote", fmt.Sprintf("%s:%s", remoteAddr, remotePort)},
 		{"interface", c.Interface},
 		{"inode", fmt.Sprintf("%d", c.Inode)},
 	}
@@ -274,7 +314,7 @@ 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 +326,179 @@ 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
@@ -312,23 +525,72 @@ type columns struct {
 }
 
 func (m model) columnWidths() columns {
-	available := m.safeWidth() - 16
-
+	// minimum widths (header lengths + padding)
 	c := columns{
-		process: 16,
-		port:    6,
-		proto:   5,
-		state:   11,
-		local:   15,
-		remote:  20,
+		process: 7,  // "PROCESS"
+		port:    4,  // "PORT"
+		proto:   5,  // "PROTO"
+		state:   5,  // "STATE"
+		local:   5,  // "LOCAL"
+		remote:  6,  // "REMOTE"
 	}
 
-	used := c.process + c.port + c.proto + c.state + c.local + c.remote
-	extra := available - used
+	// scan visible connections to find max content width for each column
+	visible := m.visibleConnections()
+	for _, conn := range visible {
+		if len(conn.Process) > c.process {
+			c.process = len(conn.Process)
+		}
 
-	if extra > 0 {
-		c.process += extra / 3
-		c.remote += extra - extra/3
+		port := m.resolvePort(conn.Lport, conn.Proto)
+		if len(port) > c.port {
+			c.port = len(port)
+		}
+
+		if len(conn.Proto) > c.proto {
+			c.proto = len(conn.Proto)
+		}
+
+		if len(conn.State) > c.state {
+			c.state = len(conn.State)
+		}
+
+		local := m.resolveAddr(conn.Laddr)
+		if len(local) > c.local {
+			c.local = len(local)
+		}
+
+		remote := m.formatRemote(conn.Raddr, conn.Rport, conn.Proto)
+		if len(remote) > c.remote {
+			c.remote = len(remote)
+		}
+	}
+
+	// calculate total and available width
+	spacing := 12 // 2 spaces between each of 6 columns
+	indicator := 2
+	margin := 2
+	available := m.safeWidth() - spacing - indicator - margin
+
+	total := c.process + c.port + c.proto + c.state + c.local + c.remote
+
+	// if content fits, we're done
+	if total <= available {
+		return c
+	}
+
+	// content exceeds available space - need to shrink columns proportionally
+	// fixed columns that shouldn't shrink much: port, proto, state
+	fixedWidth := c.port + c.proto + c.state
+	flexibleAvailable := available - fixedWidth
+
+	// distribute flexible space between process, local, remote
+	flexibleTotal := c.process + c.local + c.remote
+	if flexibleTotal > 0 && flexibleAvailable > 0 {
+		ratio := float64(flexibleAvailable) / float64(flexibleTotal)
+		c.process = max(7, int(float64(c.process)*ratio))
+		c.local = max(5, int(float64(c.local)*ratio))
+		c.remote = max(6, int(float64(c.remote)*ratio))
 	}
 
 	return c
@@ -350,3 +612,29 @@ func formatDuration(d time.Duration) string {
 	}
 	return fmt.Sprintf("%.0fm", d.Minutes())
 }
+
+func (m model) resolveAddr(addr string) string {
+	if !m.resolveAddrs {
+		return addr
+	}
+	if addr == "" || addr == "*" {
+		return addr
+	}
+	return resolver.ResolveAddr(addr)
+}
+
+func (m model) resolvePort(port int, proto string) string {
+	if !m.resolvePorts {
+		return strconv.Itoa(port)
+	}
+	return resolver.ResolvePort(port, proto)
+}
+
+func (m model) formatRemote(addr string, port int, proto string) string {
+	if addr == "" || addr == "*" || port == 0 {
+		return "-"
+	}
+	resolvedAddr := m.resolveAddr(addr)
+	resolvedPort := m.resolvePort(port, proto)
+	return fmt.Sprintf("%s:%s", resolvedAddr, resolvedPort)
+}

main.go

@@ -1,7 +1,7 @@
 package main
 
 import (
-	"snitch/cmd"
+	"github.com/karol-broda/snitch/cmd"
 )
 
 func main() {