Sort apache access logs and convert 'common' into 'combined'. The output of this script can be used as input for awffull or webalizer.

sort-access-log

#!/bin/bash
###
# Sorts the rows of one or multiple apache access_log files
# by date (ascending) and converts them from 'common' log format
# into 'combined' (if you switched the log file format meanwhile).
#
# This is useful when you want to merge multiple log files, e.g. when
# you have different files for HTTP and HTTPS.
#
# Usage:
#     sort-access-log [file [file...]]
#
# If the argument ends on .gz it will be extracted using 'gunzip'.
# If no argument has been given the script expects the input on STDIN.
#
# The date is expected to have the following format, which must occur
# *anywhere* within the line:
#
#    [20/Mar/2017:12:00:37 +0100]
#
# The timezone argument is ignored, so this might be inaccurate when
# changing from summer time to winter time - for me this doesn't matter.
#
# The output of the program can be used as input for awffull or
# webalizer.
#
# Autor: Roland Tapken <roland@dau-sicher.de>
# Datum: 2017-06-23
# License: Beerware
###

(
	if [[ "$#" -gt 0 ]]; then
		for n in $*; do
			if [[ ! -f "$n" ]]; then
				echo "Ignoring missing file '$n'" >&2
			elif [[ "$n" == *.gz ]]; then
				gunzip -c "$n"
			else
				cat "$n"
			fi
		done
	else
		# Read from stdin
		cat
	fi
) \
	| sed \
		-re 's|.*\[([0-9]{2})/([a-z]+)/([0-9]{4}):([0-9]{2}):([0-9]{2}):([0-9]{2})|\3-\2-\1\4\5\6 \0|i' \
		-e 's/-jan-/01/i' \
		-e 's/-feb-/02/i' \
		-e 's/-mar-/03/i' \
		-e 's/-apr-/04/i' \
		-e 's/-may-/05/i' \
		-e 's/-jun-/06/i' \
		-e 's/-jul-/07/i' \
		-e 's/-aug-/08/i' \
		-e 's/-sep-/09/i' \
		-e 's/-oct-/10/i' \
		-e 's/-nov-/11/i' \
		-e 's/-dec-/12/i' \
	| sort \
	| sed -re 's/^[0-9]+ //' -e 's/" [0-9]+ [0-9]+$/\0 "-" "-"/'

Works beautifully. Thank you!