epubgrep.sh

#! /usr/bin/env bash

if [[ -z $1 ]]; then
  printf "Usage: %s: <grep arguments> [filename]\n" "$(basename "$0")"
  exit 1
fi

function _grep {
  PRINT_FILENAME="$1"
  FILENAME="$2"
  BASENAME="$(basename "$2" .epub)"
  MATCHES=1
  for FILENAME_IN_ZIP in $(unzip -Z1 "$FILENAME" | grep -P '.*\.html'); do
    if (unzip -p-L "$FILENAME" "$FILENAME_IN_ZIP" | \
      sed -e 's/<[^>]*>//g' | \
      sed -e '/^[[:space:]]*$/d' | \
      sed -e 's/^[[:space:]]*//g' | \
      while IFS= read -r line; do
        if $PRINT_FILENAME; then
          echo -n -e "\e[31m$BASENAME\e[0m: ";
        fi
        echo "$line";
      done) | grep "${@:3}"; then
        MATCHES=0
      fi
  done
  return $MATCHES
}

if [[ -f "${@:$#}" ]]; then
  _grep "false" "${@:$#}" "${@:1:$(($#-1))}";
  exit $?
fi

FIRST=true
while IFS='' read -r -d '' FILENAME; do
  OUTPUT=$(_grep "true" "$FILENAME" "$@";)
  if [[ $? == 0 ]]; then
    if ! $FIRST; then
      echo
    fi
    echo "$OUTPUT"
  else
    echo -n .
  fi
  FIRST=false
done < <(find . -type f  -name '*.epub' -print0)