bash “echo 0 > foo”是什么意思？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/25769926/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
What does 'echo 0 > foo' mean?
提问by 0leg
I would like to know what does this code mean?
我想知道这段代码是什么意思？
echo 0 > foo
Completely new to Unix and Bash commands. Lots of stuff to learn, but need a quick answer to this question.
对 Unix 和 Bash 命令来说是全新的。很多东西要学习，但需要快速回答这个问题。
回答by James
The command echo 0 > foooverwrites whatever content is in the file foo- or creates it if it doesn't exist - and replaces it with 0.
该命令会echo 0 > foo覆盖文件中的任何内容foo- 或者如果它不存在则创建它 - 并将其替换为0.
The command echo 0 >> foowill add 0to the end of the file foo, or create a file containing 0if it doesn't exist.
该命令echo 0 >> foo将添加0到文件的末尾foo，或者创建一个包含文件（0如果它不存在）。
回答by j08691
It echoes 0to a file named foo. In other words, it redirects the output, 0, to a file named "foo", instead of showing it on the screen.
它回显0到一个名为foo. 换句话说，它将输出 0 重定向到名为“foo”的文件，而不是将其显示在屏幕上。
From a basic Wikipediaexample on redirection:
来自关于重定向的基本维基百科示例：
command1 > file1executes command1, placing the output in file1, as opposed to displaying it at the terminal, which is the usual destination for standard output.
command1 > file1执行 command1，将输出放在 file1 中，而不是在终端显示它，终端是标准输出的常用目的地。
