#!/bin/bash
pids=($(ps aux |
  grep '[0-9] .*node.* /home/user/client' |
  while read user pid rest; do 
    echo $pid; 
  done))

if [[ "${pids}" != "" ]]; then
  echo "Killing ${pids[@]}."
  kill ${pids[@]}
else
  echo "Running client not found."
fi