Rename files using os.listdir and matches, then re.sub, and os.rename

rename_timestamped_files.py

# Get files 
import os
import re

# os.expanduser provides the right username based on the current user
target_files = [x for x in os.listdir(os.path.expanduser('~/Downloads'))
                   if x.lower().endswith('.pdf')
                  and x.startswith('2025_')     # comment out if needed
                  and x.find('_recepit') != -1  # comment out if needed
]

# Change search_regexp and substitute_regexp as needed
search_regexp = r'(\d{4})_(\d{2})_(\d{2})_(\d{2})_(\d{2})_(\d{2})_(\d{3})_(.*pdf)'
substitute_regexp = r'\1-\2-\3.\4\5.\8'

# List the new names together with the old in a list of tuples
old_and_new_file_names = [
  (file, re.sub(search_regexp, substitute_regexp, file))
  for file in target_files
]

# Use os.rename to rename from the old to the new
for old_file_name, new_file_name in old_and_new_file_names:
  os.rename(old_file_name, new_file_name)