问题描述
哪里是按照本缓冲......？我怎么把它关掉？
Where is the buffer in this following ... and how do I turn it off?
我写出来到stdout在Python程序，像这样：
I am writing out to stdout in a python program like so:
for line in sys.stdin:
print line
有一些缓冲的事情在这里：
There is some buffering going on here:
tail -f data.txt | grep -e APL | python -u Interpret.py
我尝试以下，以摆脱可能的缓冲......有没有运气：
I tried the following to shake off possible buffering ... with no luck:
- 如上使用-u标志使用Python调用
- 每个sys.stdout.write函数调用后sys.stdout.flush（）（）调用
......所有这些创建蟒蛇等待像一分钟，打印出来的前几行缓冲流。 -
使用以下修改的命令：
- as above using the -u flag with python invocation
- calling sys.stdout.flush() after each sys.stdout.write() call... all of these create a buffered stream with python waiting something like a minute to print out the first few lines.
used the following modified command:
stdbuf -o0尾-f的data.txt | stdbuf -o0 -i0的grep -e APL | stdbuf -i0 -o0蟒蛇-u国米pret.py
stdbuf -o0 tail -f data.txt | stdbuf -o0 -i0 grep -e APL | stdbuf -i0 -o0 python -u Interpret.py
要基准我的期望，我想：
To benchmark my expectations, I tried:
tail -f data.txt | grep -e APL
这行产生了源源不断的......它肯定不是作为缓冲的python命令。
This produces a steady flow of lines ... it surely is not as buffered as the python command.
所以，我怎么关闭缓冲？
回答：原来有在管的两端缓冲
So, how do I turn off buffering?ANSWER: It turns out there is buffering on both ends of the pipe.
推荐答案
这个问题，我相信是的grep 缓冲它的输出。它这样做，当你管尾-f | grep的... | some_other_prog 。要获得的grep 每行冲洗一次，使用 - 行缓冲选项：
The problem, I believe is in grep buffering its output. It is doing that when you pipe tail -f | grep ... | some_other_prog. To get grep to flush once per line, use the --line-buffered option:
% tail -f data.txt | grep -e APL --line-buffered | test.py
APL
APL
APL
其中， test.py 是：
import sys
for line in sys.stdin:
print(line)
（测试在Linux上，GNOME终端）。
(Tested on linux, gnome-terminal.)
这篇关于关闭缓冲的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！