replacement="learn_punjabi_as_english_speaker_lesson"

for file in ~/Desktop/learn_punjab_book/concat/*.mp3; do
    # Read the file content
    content=$(cat "$file")
    
    # Replace the first 5 characters
    new_content="${replacement}${content:5}"
    
    # Write the new content back to the file
    echo "$new_content" > "$file"
done