子プロセスの標準入力に書き込む

gistfile1.txt

$ python write_stdin.py
6
20
13

write_stdin.py

#!/usr/bin/env python

from subprocess import Popen, PIPE

p = Popen(['perl', '-nle', 'print length'], stdin=PIPE)
p.stdin.write("output\n")
p.stdin.write("number of characters\n")
p.stdin.write("for each line\n")
p.stdin.close()