Bash batch rename

#!/bin/bash

# Read the old substring from user input
read -p "Enter the substring to replace: " old_substring

# Read the new substring from user input
read -p "Enter the new substring: " new_substring

# Loop over all files in the current directory that contain the old substring
for file in *"$old_substring"*; do
  # Rename the file by replacing the old substring with the new substring
  # The string manipulation uses parameter expansion
  # this method allows a regex-like string manipulation
  new_file="${file/$old_substring/$new_substring}"
  mv -- "$file" "$new_file"
  # Echo the new file name
  printf "$file\t->\t$new_file\n"
done