Bash script to remove all empty pages from any pdf in the current directory

PDFpagedelete.sh

#!/bin/bash

# Ensure the required tools are installed
command -v pdfimages >/dev/null 2>&1 || { echo >&2 "pdfimages (poppler-utils) is required but it's not installed. Exiting."; exit 1; }
command -v convert >/dev/null 2>&1 || { echo >&2 "convert (ImageMagick) is required but it's not installed. Exiting."; exit 1; }
command -v tesseract >/dev/null 2>&1 || { echo >&2 "tesseract is required but it's not installed. Exiting."; exit 1; }
command -v pdftk >/dev/null 2>&1 || { echo >&2 "pdftk is required but it's not installed. Exiting."; exit 1; }

count_letters() {
    echo "$1" | grep -o -i '[a-z]' | wc -l
}

# Create a temporary directory
tmp_dir=$(mktemp -d)

# Process PDFs recursively through subdirectories
find . -type f -name '*.pdf' | while IFS= read -r pdf; do
    total_pages=$(pdfinfo "$pdf" | grep Pages | awk '{print $2}')
    pages_to_keep=""

    for ((page=0; page<total_pages; page++)); do
        pdfimages -f $((page+1)) -l $((page+1)) "$pdf" "$tmp_dir/page_$page"
        imgs_exist=$(ls "$tmp_dir"/page_${page}-*.{ppm,pbm} 2>/dev/null | wc -l)

        if [[ $imgs_exist -gt 0 ]]; then
            for img in "$tmp_dir"/page_${page}-*.{ppm,pbm}; do
                if [[ -f "$img" ]]; then
                    convert "$img" "${img%.*}.tiff"
                    rm "$img"
                fi
            done

            has_text=false
            for tiff in "$tmp_dir"/page_${page}-*.tiff; do
                if [[ -f "$tiff" ]]; then
                    tesseract "$tiff" "${tiff%.*}"
                    rm "$tiff"
                fi
            done

            for txt in "$tmp_dir"/page_${page}-*.txt; do
                if [[ -f "$txt" ]]; then
                    text=$(cat "$txt")
                    if [[ $(count_letters "$text") -ge 4 ]]; then
                        pages_to_keep="${pages_to_keep}$((page+1)) "
                        has_text=true
                        break
                    fi
                    rm "$txt"
                fi
            done
            if [[ "$has_text" == false ]]; then
                echo "Page $((page+1)) in $pdf is empty!"
            fi
        else
            pages_to_keep="${pages_to_keep}$((page+1)) "
        fi
    done

    if [[ -n $pages_to_keep ]]; then
        # Extract pages without modifications
        pdftk "$pdf" cat $pages_to_keep output "${pdf}.tmp"
        mv "${pdf}.tmp" "$pdf"
    else
        echo "All pages in $pdf are empty. No changes made."
    fi

    rm -rf "$tmp_dir"/*
done

rm -rf "$tmp_dir"