Dev servers in git worktrees: ports and leftovers

Each worktree is a full checkout with the same config, so every copy asks for the same port. Vite quietly moves to the next free port, which makes it easy to open the wrong branch; Next.js, Rails and most others just fail with “address already in use”.

Pass the port when you start the server, and make Vite fail instead of moving:

npx vite --port 5174 --strictPort
PORT=3001 npm run dev        # Next.js, Express and most Node servers
bin/rails server -p 3001

To stop picking numbers by hand, derive the port from the branch, so the same branch always gets the same port:

PORT=$((3100 + $(git branch --show-current | cksum | cut -d' ' -f1) % 900)) npm run dev

For Vite, pass it on: npx vite --port $PORT --strictPort. Vite doesn’t read PORT on its own.

git worktree remove deletes the folder but leaves running processes alone. This prints the PID of every process whose working folder is inside the worktree, so you can stop them first:

dir=$(cd ../shop-fix && pwd -P)
lsof -a -d cwd -Fpn | awk -v d="$dir" '/^p/{p=substr($0,2)} /^n/{n=substr($0,2); if (n==d || index(n, d"/")==1) print p}'

Check what they are with ps -p <PID>, stop them with kill <PID>, then remove the worktree.

Coding agents create and delete worktrees on their own, so the folder is often gone before you notice the server. A listening process whose working folder no longer exists is a leftover:

for pid in $(lsof -tiTCP -sTCP:LISTEN | sort -u); do
  cwd=$(lsof -a -p "$pid" -d cwd -Fn | sed -n 's/^n//p')
  [ -n "$cwd" ] && [ ! -d "$cwd" ] && echo "$pid $cwd"
done

61504 /Users/you/code/shop-fix

Portlivo shows the branch on every row and keeps worktrees of the same repo next to each other, so shop on main and shop on fix are easy to tell apart. Servers whose folder is gone get their own Leftover section with Stop All, which stops only those. Agents can do the same through Portlivo’s MCP server, and servers Claude Code or Codex started are marked too: see AI agent servers.