Reimplementation of basic Unix-style tree command in Python.

tree.py

#! /usr/bin/env python
"""Reimplementation of basic Unix-style tree command in Python 3."""

import argparse
from os import listdir, path


def print_tree(top, prefix=''):
    print('{prefix}{base_name}'.format(
        prefix=prefix, base_name=path.basename(top)))
    prefix = prefix.replace('└──', '   ').replace('├──', '|  ')
    try:
        children = listdir(top)
    except OSError as e:
        return
    children = sorted(children)
    for name in children[:-1]:
        print_tree(path.sep.join([top, name]),
                   prefix='{prefix}├── '.format(prefix=prefix))
    if children:
        print_tree(path.sep.join([top, children[-1]]),
                   prefix='{prefix}└── '.format(prefix=prefix))


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('directory')

    args = parser.parse_args()
    print_tree(args.directory)