solving Arch Linux registration "Captcha" in pure shell script

Arch_Linux_Captcha.sh

#!/bin/bash
# only need bash for md5

set -eu

eval "curl(){ '$(which curl)' \"\$@\"; }" # only curl needed for md5 source;
# TODO/CONSIDER:  https://stackoverflow.com/q/7765004 "TCP connection, bash only". also needs to resolve domain.

PATH='' # enshure we are pure shell


main() {
	#!/bin/sh

	# solving Arch Linux registration "Captcha" in pure shell script
	# > To protect the AUR against automated account creation,
	# > we kindly ask you to provide the output of the following
	# > command: `LC_ALL=C pacman -V|sed -r 's#[0-9]+#e77#g'|md5sum|cut -c1-6`
	#
	# what, copy/pasting to terminal from internet.. NO! let me just sh it
	# and yes in the end it worked! I registrated using the output from this script :D

	{
		# src: https://gitlab.archlinux.org/pacman/pacman/-/blob/ff7c6c8e570bcf5e07876397af864adf8cbf2987/src/pacman/pacman.c#L240-250
		printf "\n"
		printf " .--.                  Pacman v%s - libalpm v%s\n" ${RANDOM}.${RANDOM}.${RANDOM} ${RANDOM}.${RANDOM}.${RANDOM}
		printf "/ _.-' .-.  .-.  .-.   Copyright (C) 2006-2022 Pacman Development Team\n"
		printf "\\  '-. '-'  '-'  '-'   Copyright (C) 2002-2006 Judd Vinet\n"
		printf " '--'\n"
		printf "                       This program may be freely redistributed under\n"
		printf "                       the terms of the GNU General Public License.\n"
		printf "\n"
	} | {
		# for string replacing consider: https://github.com/kisslinux/kiss/blob/990eba374e685b841266ce025773e62af93912db/kiss#L106-L118

		# wokrs, but too much of recursion
		#s() {
		#	case $1 in
		#		*[0-9]*) printf %s\\n "$(s "${1%[0-9]*}")e77${1##*[0-9]}";;
		#		*) printf %s\\n "$1";;
		#	esac
		#}

		# sed -r 's#[0-9]+#???#g' # note: replaced string in '???' seems to be randomized
		while IFS= read -r i; do
			#for bash just use: ( shopt -s extglob; echo "${i//+([0-9])/e77}" )
			while case $i in *[0-9]*) ;; *) false; esac; do
				printf %s "${i%%[0-9]*}${1:?'usage: ${0##*/} <replace digit string>'}";
				i=${i#*[0-9]}
				while case $i in [0-9]*) ;; *) false; esac; do
					i=${i#?}
				done
			done
			printf %s\\n "$i"
		done

	} | md5sum | {
		# cut -c1-6
		read i
		printf %s\\n "${i%"${i#??????}"}"
	}

}


md5sum() { ( # src: https://raw.githubusercontent.com/waldner/baSHA123/190b1a225d616a60463e00196c3d1bd57036bd25/md5.sh
	#!/bin/bash
	set +e
	if [ -f ./md5.bash ]; then
		. ./md5.bash
	else
		eval "$(curl -sL https://raw.githubusercontent.com/waldner/baSHA123/190b1a225d616a60463e00196c3d1bd57036bd25/md5.sh)"
	fi
); }


main "$@"