如何使任何 shell 命令的输出无缓冲? [英] How to make output of any shell command unbuffered?

问题描述

有没有办法在没有输出缓冲的情况下运行 shell 命令?

Is there a way to run shell commands without output buffering?

例如，hexdump 文件 |./my_script 只会将输入从 hexdump 以缓冲块的形式传递给 my_script，而不是逐行传递.

For example, hexdump file | ./my_script will only pass input from hexdump to my_script in buffered chunks, not line by line.

实际上我想知道如何使任何命令无缓冲的通用解决方案?

Actually I want to know a general solution how to make any command unbuffered?

推荐答案

AFAIK，如果没有丑陋的黑客，你就无法做到.写入管道(或从中读取)会自动打开完整缓冲，您对此无能为力:-(.行缓冲"(这是您想要的)仅在读取/写入终端时使用.丑陋的黑客正是这样做的:他们将程序连接到伪终端，以便管道中的其他工具以行缓冲模式从该终端读/写.整个问题描述如下:

AFAIK, you can't do it without ugly hacks. Writing to a pipe (or reading from it) automatically turns on full buffering and there is nothing you can do about it :-(. "Line buffering" (which is what you want) is only used when reading/writing a terminal. The ugly hacks exactly do this: They connect a program to a pseudo-terminal, so that the other tools in the pipe read/write from that terminal in line buffering mode. The whole problem is described here:

• http://www.pixelbeat.org/programming/stdio_buffering/

该页面还有一些建议(前面提到的丑陋的黑客")该怎么做，即使用 unbuffer 或使用 LD_PRELOAD 拉一些技巧.

The page has also some suggestions (the aforementioned "ugly hacks") what to do, i.e. using unbuffer or pulling some tricks with LD_PRELOAD.

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