Free Up Port

#!/bin/zsh
# @docktopus.schemaVersion 1
# @docktopus.title Free Up Port
# @docktopus.mode inline
# @docktopus.icon xmark.octagon
# @docktopus.keyword killport
# @docktopus.description Stops the processes listening on a TCP port, such as a dev server left running on 3000. Asks before it runs.
# @docktopus.argument1 {"type": "text", "placeholder": "Port"}
# @docktopus.needsConfirmation true
# @docktopus.author Docktopus

port="$1"
if [[ "$port" != <-> ]] || (( port < 1 || port > 65535 )); then
  echo "“$port” is not a port number." >&2
  exit 1
fi

pids=(${(f)"$(/usr/sbin/lsof -nP -tiTCP:"$port" -sTCP:LISTEN 2>/dev/null)"})
if (( ${#pids} == 0 )); then
  echo "Nothing is listening on port $port."
  exit 0
fi

for pid in $pids; do
  name=$(/bin/ps -p "$pid" -o comm= 2>/dev/null)
  if kill "$pid" 2>/dev/null; then
    echo "Stopped ${name:t} (PID $pid)."
  else
    echo "Could not stop ${name:t} (PID $pid). It may belong to another user." >&2
  fi
done

# Give processes a moment to exit, then report anything still holding the port.
sleep 1
if /usr/sbin/lsof -nP -tiTCP:"$port" -sTCP:LISTEN >/dev/null 2>&1; then
  echo "Port $port is still in use. Run again to retry."
else
  echo "Port $port is free."
fi