copy_dir.py

import os
import sys
import shutil


def copy_tree(src, dst):
    '''
    Copy a directory tree from src to dst ignoring dangling
    symlinks, retrieving files symlinks point to, and
    breaking the cycles, i.e. never copying the same
    source file twice.
    '''
    os.mkdir(dst)
    visited_source_paths = set()
    stack = []
    for item in os.listdir(src):
        stack.append(item)
    while stack:
        current_path_suffix = stack.pop()
        current_path = os.path.join(src, current_path_suffix)
        print(current_path)
        if os.path.realpath(current_path) in visited_source_paths:
            continue
        if os.path.islink(current_path):
            realpath = os.path.realpath(current_path)
            print(f'-> {realpath}')
            # Skip dangling and circular symlinks.
            if not os.path.exists(realpath) or realpath in visited_source_paths:
                continue
            # We assume for simplicity that the stuff valid symlinks point to is valid.
            shutil.copytree(realpath, os.path.join(
                dst, current_path_suffix), ignore=shutil.ignore_patterns('*.pyc'))
        elif os.path.isdir(current_path):
            # Create the directory in the destination tree,
            # add the contents to the stack, and continue.
            os.mkdir(os.path.join(dst, current_path_suffix))
            for item in os.listdir(current_path):
                stack.append(os.path.join(current_path_suffix, item))
        else:
            # A simple file.
            if not current_path.endswith('.pyc'):
                shutil.copy(current_path, os.path.join(
                    dst, current_path_suffix))
        visited_source_paths.add(os.path.realpath(current_path))


if __name__ == '__main__':
    src = sys.argv[1]
    dst = sys.argv[2]
    copy_tree(src, dst)