IOError: [Errno 2] Python script to parse txt files

Question

I'm starting a python script to parse a number of small text files in a folder. I need to retrieve particular information that will always be different (in this case hostname, model & serial number for a Cisco switch) and so can't use a regular expression. However I can easily find the line that contains the information. This is what I have so far:

import os

def parse_files(path):
    for filename in os.listdir(path):
        with open(filename,'r').read() as showfile:
            for line in showfile:
                if '#sh' in line:
                    hostname = line.split('#')[0]
                if 'Model Number' in line:
                    model = line.split()[-1]
                if 'System serial number' in line:
                    serial = line.split()[-1]
        showfile.close()

path = raw_input("Please specify Show Files directory: ")

parse_files(path)

print hostname,model,serial

This, however, is returning:

Traceback (most recent call last):
  File "inventory.py", line 17, in <module>
    parse_files(path)
  File "inventory.py", line 5, in parse_files
    with open(filename,'r').read() as showfile:
IOError: [Errno 2] No such file or directory: 'Switch01-run.txt'

where 'Switch01-run.txt' is a file in the specified folder. I can't figure out where I'm taking a wrong turn.

Answer 1

The problem is that os.listdir() is returning the filenames from the directory, not the complete path to the file.

You need to do this instead:

with open(os.path.join(path,filename),'r') as showfile:

This fixes two issues - the IOerror, and the error you will get trying to read lines from a string.