bash script to test if a process is running and do an action if it is or isn't

testrunning.sh

#!/bin/bash

PROCESS_GREP_STRING=eth
PROCESS_COUNT_THRESHOLD=3
SLEEP_TIMEOUT=5
RUNNING_COMMAND="echo 'Running'"
NOT_RUNNING_COMMAND="echo 'Not Running'"

while :
do

  PROCESS_COUNT=$(ps a|grep $PROCESS_GREP_STRING|wc -l)

  if [ "$PROCESS_COUNT" -ge "$PROCESS_COUNT_THRESHOLD" ]
  then
    eval $RUNNING_COMMAND
  else
    eval $NOT_RUNNING_COMMAND
  fi

  sleep $SLEEP_TIMEOUT

done