Python标准输出和子

Question

我有两个文件：

run.py

import subprocess 
import time 

while True: 
    time.sleep(1) 
    print 'hello' 
    proc = subprocess.call(['./writer.sh']) 

writer.sh（CHMOD 777'd）

#!/bin/sh 
echo 'write something here' 

，我很困惑通过以下输出：

$ python run.py 
hello 
write something here 
hello 
write something here 
hello 
write something here 
.... 

$ python run.py | tee out.log 
write something here 
write something here 
(hello disappears) 

.... 

$ python run.py > out.log 
# Nothing, but out.log has the following: 
write something here 
write something here 
write something here 
write something here 
hello 
hello 
hello 
hello 
... # and the two basically "expand" the longer I run this (instead of appending) 

什么我发生什么事了，我怎样才能像第一个命令一样输出所有内容？

Answer 1

您的主脚本的输出被缓冲。在运行子进程之前，请致电sys.stdout.flush()。