mid

#!/usr/bin/env python3

"""
Prints the Nth line of a file or of each of a list of files.
Default input stream is sys.stdin.

Usage:
   mid [-v] LINENO FILE1 [FILE2 FILE3 ...]
   cat FILE | mid LINENO
where LINENO is the 1-indexed line number to display (or a range: M-N).
If `-v` is present, it will print a UNIX `head`-style header above each
file, identifying its provenance.

Author: Matt Post <post@cs.jhu.edu>
"""

import os
import sys
import gzip
import argparse
from itertools import zip_longest

def main(args):
    if '-' in args.lines:
        start, stop = map(lambda x: int(x), args.lines.split('-'))
    elif '+' in args.lines:
        start, stop = map(lambda x: int(x), args.lines.split('+'))
        stop = start + stop
    else:
        start = int(args.lines)
        stop = int(args.lines)

    for i, lines in enumerate(zip_longest(*args.files), 1):
        if i < start:
            continue
        if i > stop:
            break

        for j, line in enumerate(lines):
            if line is not None:
                if args.verbose:
                    print('=== {}'.format(args.files[j].name), line.rstrip(), '', sep='\n')
                else:
                    print(line.rstrip(),)

def smart_read(filename: str):
    try:
        if filename == '-':
            return sys.stdin
        elif filename.endswith('.gz'):
            return gzip.open(filename, mode='rt', encoding='utf-8')
        else:
            return open(filename, mode='rt', encoding='utf-8')
    except FileNotFoundError as e:
        print("Can't find file '{}'".format(filename))
        sys.exit(1)


if __name__ == '__main__':
    parser = argparse.ArgumentParser('Grabs a line from one or more files')
    parser.add_argument('--verbose', '-v', default=False, action='store_true',
			help='Display head-style file headers if there is more than one file')
    parser.add_argument('lines',
			help='The line number (N) or range (M-N or M:N) to display')
    parser.add_argument('files',
                        nargs='*',
                        type=smart_read,
                        default=[sys.stdin],
			help='The files to work with')
    args = parser.parse_args()

    main(args)