Kill all pids listening on open port

kill-port.sh

#!/bin/bash

find_pids() {
  local port=$1

  if command -v ss &>/dev/null; then
    ss -lptn "sport = :$port" 2>/dev/null \
      | grep -oP 'pid=\K[0-9]+' \
      | sort -u # one PID per line
  elif command -v lsof &>/dev/null; then
    lsof -t -i:"$port"
  else
    echo "Neither ss nor lsof found." >&2
    return 1
  fi
}

#— main —#
[ -z "$1" ] && {
  echo "Usage: $0 <port>"
  exit 1
}
PORT=$1

# Get PIDs as a space-separated list
PIDS=$(find_pids "$PORT" | tr '\n' ' ')

if [ -n "$PIDS" ]; then
  echo "Killing processes on port $PORT: $PIDS"
  # shellcheck disable=SC2086  # intentional word-splitting so each PID is separate
  kill -9 $PIDS
  echo "Process(es) killed."
else
  echo "No process found on port $PORT"
fi