Introducing the os Modules

Tools in the os Modules

Table 2-1. Commonly used os module tools

Tasks	Tools
Shell variables	os.environ
Running programs	os.system, os.popen, os.execv, os.spawnv
Spawning processes	os.fork, os.pipe, os.waitpid, os.kill
Descriptor files, locks	os.open, os.read, os.write
File processing	os.remove, os.rename, os.mkfifo, os.mkdir, os.rmdir
Administrative tools	os.getcwd, os.chdir, os.chmod, os.getpid, os.listdir, os.access
Portability tools	os.sep, os.pathsep, os.curdir, os.path.split, os.path.join
Pathname tools	os.path.exists('path'), os.path.isdir('path'), os.path.getsize('path')

 

Administrative Tools

>>> os.getpid()
7980
>>> os.getcwd()
'C:\\PP4thEd\\Examples\\PP4E\\System'

>>> os.chdir(r'C:\Users')
>>> os.getcwd()
'C:\\Users'

 

Portability Constants

>>> os.pathsep, os.sep, os.pardir, os.curdir, os.linesep
(';', '\\', '..', '.', '\r\n')

 

Common os.path Tools

>>> os.path.isdir(r'C:\Users'), os.path.isfile(r'C:\Users')
(True, False)
>>> os.path.isdir(r'C:\config.sys'), os.path.isfile(r'C:\config.sys')
(False, True)
>>> os.path.isdir('nonesuch'), os.path.isfile('nonesuch')
(False, False)

>>> os.path.exists(r'c:\Users\Brian')
False
>>> os.path.exists(r'c:\Users\Default')
True
>>> os.path.getsize(r'C:\autoexec.bat')
24

>>> os.path.split(r'C:\temp\data.txt')
('C:\\temp', 'data.txt')

>>> os.path.join(r'C:\temp', 'output.txt')
'C:\\temp\\output.txt'

>>> name = r'C:\temp\data.txt'                            # Windows paths
>>> os.path.dirname(name), os.path.basename(name)
('C:\\temp', 'data.txt')

>>> name = '/home/lutz/temp/data.txt'                     # Unix-style paths
>>> os.path.dirname(name), os.path.basename(name)
('/home/lutz/temp', 'data.txt')

>>> os.path.splitext(r'C:\PP4thEd\Examples\PP4E\PyDemos.pyw')
('C:\\PP4thEd\\Examples\\PP4E\\PyDemos', '.pyw') 

 

Running Shell Commands from Script

Other os module Exports