>>> os.getcwd()
'/root/python'

>>> os.listdir(os.getcwd())
['deco.py', '6.py', 'inputfile.py', 'uniFile.py', 'oddnogen.py', 'ospathex.py', 'operate.py', 'bianliang.py', 'typecheck1.py']

>>> os.mkdir('/root/pythontest')

>>> os.environ['HOME']
'/root'
>>> os.makedirs(os.path.join(os.environ['HOME'],'test','py'))
>>> os.system('ls -lR /root/test')
/root/test:
total 4
drwxr-xr-x 2 root root 4096 2013-03-29 17:27 py
 
/root/test/py:
total 0
0

>>> os.getcwd()
'/root/python'
>>> os.chdir('/etc')
>>> os.getcwd()
'/etc'

>>> os.rmdir('/root/pythontest')
>>>

>>> os.remove('/root/pytest.py')

>>> os.rename('/root/pytest.py','/root/test.py')

>>> os.linesep
'\n'

>>> os.path.isdir('/root/python')
True

>>> os.path.isfile('/root/python')
False

>>> os.path.split(os.getcwd())
('/root', 'python')

>>> os.path.exists('/root')
True
>>> os.path.exists('/root/1.py')
False

>>> os.path.getsize('/root/python/if.py')
282

>>> os.path.dirname('/root/python/if.py')
'/root/python'
>>> os.path.basename('/root/python/if.py')
'if.py'

>>> os.path.join('/dave/test/','1.py')
'/dave/test/1.py'

>>> for file in os.listdir('/root/python'):
...   if os.path.isdir(file):
...     print file,"is a directory"
...   else:
...     print file,"is a file"
... 
deco.py is a file
inputfile.py is a file
operate.py is a file
hello.pyc is a file
userpw.py is a file
4.py is a file
answer is a directory

>>> import fileinput
>>> for eachline in fileinput.input("/root/datafile.txt"):
...   print eachline
... 
Dave
 
python
 
>>> for eachline in fileinput.input("/root/datafile.txt"):
...   print fileinput.filename()
... 
/root/datafile.txt
/root/datafile.txt
>>> for eachline in fileinput.input("/root/datafile.txt"):
...   print fileinput.lineno(),eachline
... 
1 Dave
 
2 python
 
>>> for eachline in fileinput.input("/root/datafile.txt"):
...   if fileinput.isfirstline():
...     print eachline
...   else:
...     break
... 
Dave

root@10.1.1.45:~# cat telphone.log 
027-987-1212
02187899682
021-110-9632
root@10.1.1.45:~# cat fileinputtest.py 
#!/usr/bin/python2.5
 
import fileinput
import sys
import re
 
pattern = "\d{3}-\d{3}-\d{4}"
filePath = "/root/telphone.log"
 
for eachline in fileinput.input(filePath):
  a = re.search(pattern,eachline)
  if a:
#    sys.stdout.write("============\n")
#    sys.stdout.write(eachline)
     print "============"
     print 'line:',fileinput.lineno(),'filename:',fileinput.filename(),'length:',len(eachline.strip('\n')),eachline
root@10.1.1.45:~# ./fileinputtest.py 
============
line: 1 filename: /root/telphone.log length: 12 027-987-1212
 
============
line: 3 filename: /root/telphone.log length: 12 021-110-9632