Bash Implementation of Wordle (macOS Tested)

wordle.sh

#!/usr/bin/env bash

if ! [ "${BASH_VERSINFO:-0}" -ge 4 ]
then
  echo 'Bash version >= 4 required, exiting.' 1>&2

  if command -v docker &>/dev/null
  then
    cat - <<'EOS' || true
Looks like you have Docker! Try this:
docker run --rm -it \
  -v "${PWD}/wordle.sh:/wordle.sh" \
  -v '/path/to/dict:/words' \
  -e WORDS_FILE=/words \
  bash:latest /wordle.sh
EOS
  fi

  exit 1
fi

set -o errexit -o errtrace -o nounset -o pipefail

declare -r WORDS_FILE="${WORDS_FILE:-"/usr/share/dict/words"}"
declare -ir WORD_LENGTH="${WORD_LENGTH:-"5"}"

function :printf () {
  # shellcheck disable=SC2059
  printf -- "$1" "${@:2}"
}

function :print () {
  :printf '%s' "$@"
}

function :println () {
  :printf '%s\n' "$@"
}

function :green () {
  :printf '\e[32m%s\e[0m' "$1"
}

function :yellow () {
  :printf '\e[33m%s\e[0m' "$1"
}

function :dark-gray () {
  :printf '\e[90m%s\e[0m' "$1"
}

function :print-guess () {
  local word="${1^^}" guess="${2^^}"

  {
    :println "${guess::${#word}}" \
      | fold -w 1 \
      | {
        : ${#word}
        nl -v 0 -w "${#_}" -n 'ln'
      }
  } | {
    while read -r offset letter
    do
      if [[ "$letter" == "${word:${offset}:1}" ]]
      then :green "$letter"
      elif [[ "$word" == *"$letter"* ]]
      then :yellow "$letter"
      else :dark-gray "$letter"
      fi
    done
  }
}

declare -a TEMP_FILES=()

function :exit () {
  :println "${TEMP_FILES[@]}" | {
    while IFS= read -r
    do
      if [[ -f "$REPLY" ]]
      then rm -f "$REPLY"
      fi
    done
  }
}

trap :exit EXIT

function :mktemp () {
  declare -g "$1"="$(mktemp)"
  TEMP_FILES+=("${!1}")
}

:mktemp TEMP_SHUFFLED_WORDS_FILE
shuf -o "$TEMP_SHUFFLED_WORDS_FILE" "$WORDS_FILE"

:mktemp TEMP_FILTERED_WORDS_FILE
grep -x -E "[a-z]{${WORD_LENGTH}}" \
  "$TEMP_SHUFFLED_WORDS_FILE" 1>"$TEMP_FILTERED_WORDS_FILE"

rm -f "$TEMP_SHUFFLED_WORDS_FILE"
unset -v TEMP_SHUFFLED_WORDS_FILE

# shellcheck disable=SC2155
declare -i WORDS="$(wc -l "$TEMP_FILTERED_WORDS_FILE" | awk '{print $1}')"

for ROUND in $(seq "$WORDS")
do
  WORD="$(sed "${ROUND}q;d" "$TEMP_FILTERED_WORDS_FILE")"

  declare -i ATTEMPTS=0

  while [[ $ATTEMPTS -lt 6 ]]
  do
    read -r -p "$((ATTEMPTS+1)): " -n "${#WORD}" GUESS

    if ! grep -x -s "${GUESS,,}" "$TEMP_FILTERED_WORDS_FILE"
    then
      :printf '\r%*s\r' "$COLUMNS"
      :printf '\r\e[31;5m%s\e[0m' 'INVALID'
      sleep 1
      :printf '\r%*s\r' "$COLUMNS"
      continue
    fi

    ((++ATTEMPTS))

    :printf '\r%s\n' "${ATTEMPTS}: $(:print-guess "$WORD" "$GUESS")"

    if [[ "${GUESS^^}" == "${WORD^^}" ]]
    then
      :println
      continue 2
    fi
  done

  :printf '\nANSWER: %s\n\n' "${WORD^^}"
done

Moved to mtthlm/bash-wordle.