Python: Searching through more than one file.

Question

I need to search through a directory of text files for a string. Here is a short program I made in the past to search through a single text file for a line of text.

How can I modify the code to search through a directory of files that have different filenames, but the same extension?

fname = raw_input("Enter file name: ") #"*.txt"
fh = open(fname)
lst = list()
biglst=[]
for line in fh:
 line=line.rstrip()
 line=line.split()
 biglst+=line
final=[]
for out in biglst:
 if out not in final:
 final.append(out)
final.sort()
print (final)

Answer 1

There are multiple ways to this.

1) Using glob module.

import glob
import os
result_file_list=[]
search_string=raw_inout("Enter the search string: ")
file_extension=raw_input("Enter file extension: ")
os.chdir("/mydir")  #Use absolute pathname of the directory in place of mydir
for file in glob.glob("*." + file_extension):
    with open(file,r'rb') as search_file:
        lines=search_file.readlines()
    for line in lines:
        line=line.strip()
        if search_string in line:
            result_file_list.append(file)

print  "Files containing the string being searched are: "
for file in result_file_list:
    print file

2) Using subprocess module. This is similar to using shell script.

import sys
import subprocess
file_extension=raw_input("Enter file extension: ") 
proc=subprocess.Popen("ls -LR " + "/MYDIRECTORYFULLPATH" + " | grep ."+                                
                                                                  search_extension,stdout=subprocess.PIPE,shell=True)
stdout,stderr=proc.communicate()
stdout=stdout.strip().split("\n")

Now stdout gives u the list of all files with the required extension. Now iterate through the list of files and do as done above or whatever is your requirement.