There's not much to see here, bar the following:
tail -f $1
| perl -pe 's/(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}) (.+) (.+) \[(.+)\] \"([A-Z]{3,4}) (\/.*) (HTTP\/1\.[01])\" (\d+) (.+) \"(.+?)\" \"(.+?)\"/\e[1m$1\e[0m \e[36m$2\e[0m \e[36m$3\e[0m [\e[34m$4\e[0m] "\e[1m$5\e[0m \e[32m$6\e[0m \e[31m$7\e[0m" \e[1m$8\e[0m \e[1m$9\e[0m "\e[32m$10\e[0m" "$11"/g'