import os
import os.path
import shutil
import errno
import glob
import sys
# Be python3 ready
from __future__ import unicode_literals, print_function
1- The os.path module seems verbose but it's the best way to manage paths. It's:
2- Here we check the operating system and prepend the right path
import os
import sys
basedir, hosts = "/", "etc/hosts"
# sys.platform shows the current operating system
if sys.platform.startswith('win'):
basedir = 'c:/windows/system32/drivers'
print(basedir)
# Join removes redundant "/"
hosts = os.path.join(basedir, hosts)
print(hosts)
# normpath fixes "/" orientation
# and redundant ".."
hosts = os.path.normpath(hosts)
print("Normalized path is", hosts)
# realpath resolves symlinks (on unix)
! mkdir -p /tmp/course
! ln -sf /etc/hosts /tmp/course/hosts
realfile = os.path.realpath("/tmp/course/hosts")
print(realfile)
# Exercise: given the following path
base, path = "/usr", "/bin/foo"
# Which is the expected output of result?
result = os.path.join(base, path)
Python modules can: - manage directory trees - and basic errors
# os and shutil supports basic file operations
# like recursive copy and tree creation.
from os import makedirs
makedirs("/tmp/course/foo/bar")
# while os.path can be used to test file existence
from os.path import isdir
assert isdir("/tmp/course/foo/bar")
# Check the directory content with either one of
!tree /tmp/course || find /tmp/course
# We can use exception handlers to check
# what happened.
try:
# python2 does not allow to ignore
# already existing directories
# and raises an OSError
makedirs("/tmp/course/foo/bar")
except OSError as e:
# Just use the errno module to
# check the error value
print(e)
import errno
assert e.errno == errno.EEXIST
from shutil import copytree, rmtree
# Now copy recursively two directories
# and check the result
copytree("/tmp/course/foo", "/tmp/course/foo2")
assert isdir("/tmp/course/foo2/bar")
#This command should work on both unix and windows
!dir /tmp/course/foo2/
# Now remove it and check the outcome
rmtree("/tmp/course/foo")
assert not isdir("/tmp/course/foo/bar")
#This command should work on both unix and windows
!dir /tmp/course/
# Cleanup created files
rmtree("/tmp/course")