How do I find which process is using port 3000 on macOS?

Run `ports` with no arguments. It prints every listening port on the machine, hides system daemons by default, and shows the working directory and parent process for each one — so you can tell at a glance which project owns port 3000. For full detail on a single port, use `ports inspect 3000`.

How do I kill the process listening on a port on macOS?

`ports kill 3000` sends SIGTERM to the listener on port 3000. If it doesn't exit, `ports force-kill 3000` sends SIGKILL. You can also pass multiple ports or pids: `ports kill 3000 4000 12345`.

Can I kill every dev server in a project at once?

Yes. `ports kill --dir ~/code/web-app` signals every listener whose working directory is at or under that path. Use `--yes` to skip the confirmation prompt, or `force-kill --dir ...` for SIGKILL.

How do I keep Claude Code, Codex, or another AI agent running while my Mac idles?

Run `ports --find codex`, `ports --find "claude code"`, or `ports` to find the local listener, AI app, agent, tool bridge, or workspace process, then run `ports caffeinate `, `ports caffeinate `, or `ports caffeinate --pid `. Add `--follow` when newly spawned matching children should be caffeinated automatically. The `CAFFEINATE` column shows the watcher PID while active.

Can ports keep a Mac running with the lid closed?

`ports caffeinate` uses macOS's supported sleep assertion command: `/usr/bin/caffeinate -dimsu -w `. It prevents idle sleep while macOS permits it. For lid-closed runs, keep the Mac on power in a supported clamshell setup; macOS can still force sleep outside those conditions.

Does ports work on Linux or Windows?

No. ports is macOS-only and shells out to `/usr/sbin/lsof` and `/bin/ps` with macOS-specific flags. Linux and Windows ship perfectly good native tools (`ss`, `netstat`, Resource Monitor); cross-platform support would change the character of the tool.

No always-on ports daemon. There is no LaunchAgent, no SQLite, and no `~/Library` data directory. Normal invocations read live state from the kernel via lsof. When requested, `ports caffeinate` starts a normal macOS caffeinate watcher for the target PID, and that watcher exits when the process exits. `--follow` is opt-in and starts a small background watcher for that selector.

Why does my Docker port show up as `ssh` in lsof?

Colima, Lima, and OrbStack forward container ports through SSH tunnels, so plain lsof reports the listener as `ssh`. ports detects these tunnels and humanizes them as `docker( )` with the real project path, so you actually know what you're killing.

Do I need sudo to use ports?

Listing your own listeners works without sudo. Killing a port owned by root (rare on a developer machine) requires `sudo ports kill ...`. ports never installs a setuid helper.

How is ports different from lsof or netstat?

lsof and netstat answer 'what's on port 3000'. ports answers 'which project is this, when did it start, who spawned it, and can I just kill it by port number'. It also hides GUI apps and system daemons by default so the output stays signal-only.

How do I fix EADDRINUSE: address already in use on macOS?

EADDRINUSE means another process is already bound to the port your app is trying to listen on. Run `ports` to see which project owns that port (Node, Rails, Vite, Postgres, Docker tunnel — they all show up with their cwd), then `ports kill ` to free it. If the process won't exit gracefully, `ports force-kill ` sends SIGKILL.

How do I find what process is using port 8080 on macOS?

`ports --range 8080:8080` or `ports inspect 8080`. The first command lists the listener with its project path and parent process; the second adds a full process tree, started-at timestamp, and a quick HTTP probe so you know what HTTP server actually answered.

How do I free port 5432 (Postgres) on a Mac?

If you're running Postgres in Docker via Colima, Lima, or OrbStack, plain lsof reports the listener as `ssh`. ports detects the tunnel and shows `docker(postgres)` with the real container and project path. To free the port: `ports kill 5432` for a graceful shutdown, or `ports force-kill 5432` to terminate the container's tunnel immediately.

How do I kill a Node, Vite, or Next.js dev server stuck on a port?

`ports kill 3000` (or whichever port). For Vite's default 5173, `ports kill 5173`. If you've leaked several dev servers from one project, `ports kill --dir ~/code/web-app` signals every listener under that path with one confirmation. Pass `--yes` to skip the prompt.

What does 'bind: address already in use' mean on Mac?

Same root cause as EADDRINUSE — the port your server is trying to bind is already held by another process. Run `ports` to identify the holder (it'll show the project, the parent, and how long it's been running), then `ports kill ` to release it.

Does ports work on Apple Silicon (M1, M2, M3, M4) Macs?

Yes. ports ships native binaries for both Apple Silicon (arm64) and Intel (amd64). The npm postinstall script picks the right one for your machine automatically; the Homebrew tap and `go install` build natively too.

ports — project-aware lsof for macOS

Single-binary Go CLI. Shows which project owns each listening port, finds AI sessions, and caffeinates exact PIDs by port, directory, AI name, or --follow selector.

Install: brew install erdemylmaz/ports-cli/ports · npm i -g @erdemyilmaz/ports-cli · go install github.com/erdemylmaz/ports-cli/cmd/ports@latest

Keep awake: ports caffeinate codex --follow · ports caffeinate 3000 · ports --caffeinate <pid>

Source: github.com/erdemylmaz/ports-cli