#!/bin/sh

awk -vstart="$1" -vend="$2" ' 

BEGIN {
        start_epoch = mktime(start)
        end_epoch   = mktime(end)
}

function monthnumber(monthname) {
        return sprintf("%02d\n",(match("JanFebMarAprMayJunJulAugSepOctNovDec",monthname)+2))/3
}

match($0,/^([0-9]+)\/([a-zA-Z]+)\/([0-9]{4}):([0-9]{2}):([0-9]{2}):([0-9]{2})/,r) { 
        current=mktime( sprintf("%s %s %s %s %s %s", r[3],monthnumber(r[2]),r[1],r[4],r[5],r[6])); }

match($0,/^[a-zA-Z]+ ([a-zA-Z]+) ([0-9]+) ([0-9]+):([0-9]+):([0-9]+) ([0-9]{4})/,r) { 
        current=mktime( sprintf("%s %s %s %s %s %s", r[6],monthnumber(r[1]),r[2],r[3],r[4],r[5])); }

match($0,/^([0-9]+)-([a-zA-Z]+) ([0-9]+):([0-9]+):([0-9]+)/,r) { 
        current=mktime( sprintf("%s %s %s %s %s %s", strftime("%Y"),monthnumber(r[2]),r[1],r[3],r[4],r[5])); } 

(current < start_epoch) { next }
(current > end_epoch  ) { exit }

1
' | "$3"

# call is: ./logsearch "YYYY mm dd HH MM SS" "YYYY mm dd HH MM SS" logfile

./logsearch "2010 10 24 16 34 00" "2020 10 25 23 59 00" my.log