My work-in-progress "illegal character killer"

renamery.py

import collections
import itertools
import os
import pathlib
import sys

REPLACE_TUPLES = (("/.", "/"),)
REPLACE_CHARS = ':*?"![]'
VERY_REPLACE = {'$': 'S'}


def walk(path: pathlib.Path):
    if not path.exists():
        print(path, "went away")
        return

    for item in list(path.iterdir()):
        if item.is_dir():
            yield item
            yield from walk(item)
        elif item.is_file():
            yield item


def need_rename(filename: pathlib.Path):
    if filename.is_dir():
        c = collections.Counter(f.name.lower() for f in filename.parent.iterdir())
        if c[filename.name.lower()] > 1:
            newfn = next(
                f.name
                for f in filename.parent.iterdir()
                if f.name.lower() == filename.name.lower()
            )
            if filename.name != newfn:
                return filename.parent / newfn
    elif (
        any(c in str(filename) for c in REPLACE_CHARS)
        or any(c in str(filename) for c, _ in REPLACE_TUPLES)
        or filename.name.startswith(".")
    ):
        if filename.name.startswith("."):
            filename = filename.parent / ("_" + filename.name.lstrip("."))
        for c in REPLACE_CHARS:
            filename = str(filename).replace(c, "_")
        for c, v in VERY_REPLACE.items():
            filename = str(filename).replace(c, v)
        for old, new in REPLACE_TUPLES:
            filename = str(filename).replace(old, new)
        filename = str(filename).replace("/.", "/")
        np = pathlib.Path(filename)
        return np


p = pathlib.Path(".")
doit = "--do-it" in sys.argv
for file in walk(p):
    if rename_to := need_rename(file):
        print(file, "->", rename_to)
        if file.is_file():
            if doit:
                try:
                    os.makedirs(rename_to.parent)
                except:
                    pass
                os.rename(file, rename_to)
        elif file.is_dir():
            for item_to_move in file.iterdir():
                new_path = rename_to / item_to_move.name
                print("    ", item_to_move, "->", new_path)
                if doit:
                    pp = str(new_path)
                    for ii in range(1, 10):
                        try:
                            os.rename(item_to_move, pp)
                            break
                        except OSError as e:
                            pp = f"{str(new_path)}_{ii+1}"
                            print(f"     {e}: trying")
            if doit:
                os.rmdir(file)

if not doit:
    print("If you like this course of events, use --do-it and rerun")