Programming Python, 3rd Edition

Copying Directory Trees

The next three sections conclude this chapter by exploring a handful of additional utilities for processing directories (a.k.a. folders) on your computer with Python. They present directory copy, deletion, and comparison scripts that demonstrate system tools at work. All of these were born of necessity, are generally portable among all Python platforms, and illustrate Python development concepts along the way.

Some of these scripts do something too unique for the visitor module’s classes we’ve been applying in early sections of this chapter, and so require more custom solutions (e.g., we can’t remove directories we intend to walk through). Most have platform-specific equivalents too (e.g., drag-and-drop copies), but the Python utilities shown here are portable, easily customized, callable from other scripts, and surprisingly fast.

A Python Tree Copy Script

My CD writer sometimes does weird things. In fact, copies of files with odd names can be totally botched on the CD, even though other files show up in one piece. That’s not necessarily a showstopper; if just a few files are trashed in a big CD backup copy, I can always copy the offending files to floppies one at a time. Unfortunately, Windows drag-and-drop copies don’t play nicely with such a CD: the copy operation stops and exits the moment the first bad file is encountered. You get only as many files as were copied up to the error, but no more.

In fact, this is not limited to CD copies. I’ve run into similar ...