#!/bin/bash
current_time=$(date +%s)
ps axo lstart=,pid=,cmd= |
grep  "puppet agent: applying configurat" |
    while read line
    do
        # 60 * 60 is one hour, multiply additional or different factors for other thresholds
        if (( $(date -d "${line:0:25}" +%s) < current_time - 60 * 60 * 1 ))
        then
            pid=`echo $line | cut -d ' ' -f 6`    # change echo to kill
            kill $pid
        fi
    done