C Shell 流重定向的操作符说明

最新推荐文章于 2023-06-11 22:44:52 发布

原创最新推荐文章于 2023-06-11 22:44:52 发布 · 323 阅读

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#csh

本文详细解释了 tcsh shell 中文件重定向符号的使用方法及其与 noclobber 设置的关系。介绍了如何利用不同的重定向符号（如 >、>> 和 !）来控制标准输出到文件的行为，包括覆盖、追加和创建文件等操作。

http://stackoverflow.com/questions/6762348/what-do-and-do-in-tcsh 写道

In tcsh redirection the ! symbol means overwrite the existing file even if noclobber is set.

In other words, if noclobber is set then:

cmd > file will write stdout to file if file does not exist
cmd > file will fail if file exists
cmd >> file will append stdout to file if file exists
cmd >> file will fail if file does not exist
cmd >! file will write stdout to file, overwriting any existing file
cmd >>! file will append stdout to file, creating the file if it does not already exist
If noclobber is not set then the ! has no effect:

cmd > file will write stdout to file, overwriting any existing file
cmd >> file will append stdout to file
cmd >! file will write stdout to file, overwriting any existing file
cmd >>! file will append stdout to file