Finds and kills a process on a port using lsof (only tested on OSX)

killport

#!/usr/bin/env bash

# Kills a process running on a given port
#
# Examples:
# A process is running on port 3000, but we're not sure we want to kill it yet:
#
# $ killport 3000
# > Found pid 27448 running on 3000
# > tyler.montgomery 27851 0.0 0.0 2441988 684 s014 S+ 3:54PM 0:00.00 grep 27448 tyler.montgomery 27448 0.0 1.4 2727220 227784 s009 S+ 3:53PM 0:08.22 puma [app] init ...
# > Pass -f to kill process
#
# Now to kill the process, pass -f
#
# $ killport 3000 -f
# > Found pid 27448 running on 3000
# > tyler.montgomery 27851 0.0 0.0 2441988 684 s014 S+ 3:54PM 0:00.00 grep 27448 tyler.montgomery 27448 0.0 1.4 2727220 227784 s009 S+ 3:53PM 0:08.22 puma [app] init ...
# > Process killed
#
# Nothing is running on target port

# $ killport 3000 -f
# > Nothing running on 3000

port=$1
killit=$2
pid=`lsof -t -i:$1`

if [ -n "$pid" ]
then
  echo "Found pid $pid running on $port"
  process=`ps aux | grep $pid`
  echo $process

  if [ "$killit" = "-f" ]
  then
    kill -9 $pid
    echo "Process killed"
  else
    echo "Pass -f to kill process"
  fi

else
  echo "Nothing running on $port"
  exit 1
fi