Find and Kill a Specific Process by Name or Port

#!/bin/bash
# Find and kill a process by name or port

SEARCH_TERM="$1"
KILL_SIGNAL="-TERM" # Or -KILL, -INT for stronger termination

if [ -z "$SEARCH_TERM" ]; then
  echo "Usage: $0 <process_name_or_port>"
  echo "Example: $0 'node server.js'"
  echo "Example: $0 3000"
  exit 1
fi

echo "Searching for processes matching '$SEARCH_TERM'..."

PIDS=()
if [[ "$SEARCH_TERM" =~ ^[0-9]+$ ]]; then
  # Search by port
  echo "Searching by port $SEARCH_TERM..."
  # lsof -t -i :PORT gets PIDs listening on that port
  PIDS=$(lsof -t -i :"$SEARCH_TERM" 2>/dev/null)
else
  # Search by process name/command
  echo "Searching by process name '$SEARCH_TERM' ..."
  # pgrep -f searches the full command line
  PIDS=$(pgrep -f "$SEARCH_TERM" 2>/dev/null)
fi

if [ -z "$PIDS" ]; then
  echo "No processes found matching '$SEARCH_TERM'."
  exit 0
fi

echo "Found process(es) with PIDs: $PIDS"

for PID in $PIDS; do
  if [ "$PID" == "$$" ]; then # Don't kill self
    echo "Skipping self PID: $PID"
    continue
  fi
  echo "Attempting to send $KILL_SIGNAL to PID $PID..."
  kill "$KILL_SIGNAL" "$PID"
  if [ $? -eq 0 ]; then
    echo "Successfully sent $KILL_SIGNAL to PID $PID."
  else
    echo "Error sending $KILL_SIGNAL to PID $PID."
  fi
done

echo "Process termination attempt completed."
exit 0