python cat

disl

#! /usr/bin/env python3
# -*- coding: utf-8 -*-
import sys, os
import argparse
import re

def showprintings(f,endchar,showNum=False):
max_len = 4096
num = 0
prog = re.compile('\t')
prog2 = re.compile('\r\n')
if not os.path.isfile(f):
print("{}: not a file".format(f))
try:
with open(f, "rb") as fp:
for line in iter(lambda: fp.readline(max_len), b''):
line = line.decode()
if showNum == True:
num += 1
if endchar == 'Num':
if line != '\r\n':
print("{} {}".format(num, line), end='')
else:
print('')
else:
print("{} {}".format(num, line), end='')
else:
if endchar == "$":
line = prog2.sub('$', line)
print("{}".format(line), end='\n')
elif endchar == "T":
line = prog.sub('^I', line)
line = line[:-2]
print("{}".format(line), end='\n')
else:
print("{}".format(line), end='')
except Exception as e:
print(e)

def main():
usage = 'cat - concatenate files and print on the standard output'
parser = argparse.ArgumentParser(usage)
parser.add_argument('-n', action='store_true', default=False, help='number all output lines')
parser.add_argument('-b', action='store_true', default=False, help='number nonempty output lines')
parser.add_argument('-v', action='store_true', default=False, help='use ^ and M- notation, except for LFD and TAB')
parser.add_argument('-E', action='store_true', default=False, help='display $ at end of each line')
parser.add_argument('-T', action='store_true', default=False, help='display TAB characters as ^I')
parser.add_argument('-t', action='store_true', default=False, help='equivalent to -vT')

parser.add_argument("x", type=str, help="File1")
args = parser.parse_args()
if args.v:
showprintings(args.x, '', False)
elif args.E:
showprintings(args.x, '$', False)
elif args.b:
showprintings(args.x, 'Num', True)
elif args.n:
showprintings(args.x, '', True)
elif args.T or args.t:
showprintings(args.x, 'T', False)
else:
print(parser.print_help())

if __name__ == '__main__':
main()