#!/bin/bash

# Use the first argument as the directory or default to the current directory
directory="${1:-$(pwd)}"

# Change to the specified directory
cd "$directory" || { echo "Directory not found: $directory"; exit 1; }

# Regular expression to match " 00 ", " 01 ", ..., " 99 "
for file in *; do
  if [[ "$file" =~ ([[:space:]]([0-9]{2})[[:space:]]) ]]; then
    # Extract the number (e.g., "00", "01")
    number="${BASH_REMATCH[2]}"
    
    # Get the file extension
    extension="${file##*.}"
    [[ "$file" == "$extension" ]] && extension="" || extension=".$extension"

    # Construct the new filename
    new_filename="E$number$extension"

    # Rename the file
    mv -v "$file" "$new_filename"
  else
    echo "Skipped: $file (no match)"
  fi
done