grep.py

import argparse
import os 
import re

parser = argparse.ArgumentParser(description='Rough implementation of unix\
                                 command (GREP) in python')
parser.add_argument('file', metavar='F', type=str, nargs=1)
parser.add_argument('-w', '--word', type=str, nargs=1, help='Find all\
                    instances of given word in file.')
parser.add_argument('-x', '--expression', type=str, nargs=1, help='Find all\
                    instances of given expression in file.')
args = parser.parse_args()

# colors for termional output
class bcolors:
    HEADER = '\033[95m'
    OKBLUE = '\033[94m'
    OKGREEN = '\033[92m'
    WARNING = '\033[93m'
    FAIL = '\033[91m'
    ENDC = '\033[0m'
    BOLD = '\033[1m'
    UNDERLINE = '\033[4m'

# simple find implementation 
def find_string(_file, string):
    with open(_file) as f:
        for line in f.readlines():
            if line.find(string) >= 0:
                print(bcolors.OKBLUE + f"\t{line}" + bcolors.ENDC, end="")

# regex text search 
def match_string(_file, expression):
    regex = re.compile(expression)
    with open(_file) as f:
        for line in f.readlines():
            if regex.search(line):
                print(bcolors.OKBLUE + f"\t{line}" + bcolors.ENDC, end="")


if __name__ == "__main__":
    if args.word:
        find_string(args.file[0], args.word[0])
    elif args.expression:
        match_string(args.file[0], args.expression[0])