@click.command()
@click.option('-f', '--file', nargs=1, type=click.UNPROCESSED, default=False)
def main(line, word, count, std, file):
     параметр1

$ /tmp $ cat test.txt 
aBcD1!
$ /tmp $ cat test.py 
import sys

d = []
while True:
    s = sys.stdin.read(4096)
    if s == '':
        break
    d.append(s)
print(''.join(d))
$ /tmp $ cat test.txt | python3 test.py
aBcD1!