inspired by Julia Evans' (https://twitter.com/b0rk) header script from https://youtu.be/mFKrw_zTbpc ( https://changelog.fm/450 )

headers.py

#!/usr/bin/env python3

# inspired by Julia Evans' (https://twitter.com/b0rk) header script from
#   https://changelog.fm/450 ( https://youtu.be/mFKrw_zTbpc )
import fileinput

# takes stdin from visual mode of vim and ! to execute this script
lines = [ x.strip().rstrip(' #').lstrip('# ') for x in fileinput.input() ]

# getting the longest line length from the input
line_len = max(len(line) for line in lines)

# padding for 2 on either side
total_len = line_len + 4

# print starter of all #
print('#' * total_len )

# add # to beginning and end of lines
for line in lines:
    # skip output if line is empty
    if len(line) ==  0:
        continue
    print('# ', end='')
    print(line, end='')
    print(' ' * (line_len - len(line)), end='')
    print(' #')

# print final of all #
print('#' * total_len)