How to use grep in IPython?

Question

I have installed PythonXY. How do I use or install grep or a grep like function in IPython? It gives an error that grep is not defined. I want to search for text in text files in a directory.

See [using grep in python in SO](https://stackoverflow.com/questions/9018109/using-grep-in-python) — Tengis, Apr 10 '14 at 06:36
Why use grep? Why not use Python's own regex functions? Load the file and search it. — sashoalm, Apr 10 '14 at 07:20

score 3 · Answer 1 · answered Sep 01 '15 at 13:43

With just python (>=2.5) code:

import fileinput
import re
import glob

def grep(PAT, FILES):
    for line in fileinput.input(glob.glob(FILES)):
        if re.search(PAT, line):
            print fileinput.filename(), fileinput.lineno(), line

Then you can use it this way:

grep('text', 'path/to/files/*')

score 2 · Answer 2 · answered Apr 10 '14 at 07:15

Assuming you are on a *nix system you can do:

File: file_1.txt

this is line one
this is line two
this is line three

Code:

import os
import subprocess

os.system('grep one file_1.txt')
subprocess.call(['grep', 'one', 'file_1.txt'])

Output in both cases:

this is line one

How to use grep in IPython?

2 Answers2