当通过ssh传递时，为什么带引号的空格命令不起作用？

本文介绍了当通过ssh传递时，为什么带引号的空格命令不起作用？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 我正在构建此项目，在该项目中必须使用ssh执行UNIX命令。这是我的问题：在UNIX shell中执行以下命令时，I am building this project in which I have to execute UNIX commands using ssh. Here is my question : When I execute the following command in a UNIX shell,echo "Hello World"它产生输出：Hello World参数之间有5个空格用双引号引起来。我也想通过ssh达到相同的效果。我试图使用反斜杠转义双引号，如下所示：With 5 spaces in between as the arguments were given within double quotes. I want to achieve the same effects with ssh as well. I am trying to escape the double quotes using backslash as follows :ssh localhost echo \"Hello World\"因为我不希望bash处理报价。但这只会产生as I do not want bash to process the quotes. But it just producesHello World Hello之后只有一个空格为什么？There is only one space after "Hello"Why is that?推荐答案 ssh 执行一个命令，该命令是通过调用远程shell给出的，该脚本由脚本组成，该脚本由完整的本地参数集以及它们之间的空格组成。ssh executes a command it's given by invoking a remote shell with a script composed of the full set of local arguments concatenated together with whitespace between them.如果您运行：# This has only syntactic quotes -- none of the quotes are literal.ssh somehost echo "Hello World" ..然后将此参数列表传递给 ssh （使用C语法，不包括主机名和ssh命令本身）为 { echo， Hello World，NULL} 。..then this list of arguments passed to ssh (in C syntax, excluding the hostname and the ssh command itself) is { "echo", "Hello World", NULL }.连接成一个字符串，然后变成 echo Hello World 。Concatenated together into a string, this then becomes "echo Hello World".因此，远程shell运行 echo Hello World ，它没有语法引号。Thus, the remote shell runs echo Hello World, which has no syntactic quotes.如果您运行：ssh somehost echo \"Hello World\" ...然后是命令列表（再次使用C语法）是 { echo， \ Hello， World\，NULL} ：引号是文字，但空格已由本地外壳程序删除（在运行SSH之前）在分词过程中。...then the list of commands (again, in C syntax) is { "echo", "\"Hello", "World\"", NULL }: The quotes are literal, but the spaces were removed by the local shell (before SSH was run) during the word-splitting process.连接到字符串中后，它会成为 echo Hello World 。因此，您得到的是报价，但是却失去了空格。Concatenated into a string, this becomes echo "Hello World". Thus, you get quotes, but lose your spaces.相反，这是可行的（但不是最佳实践） ）示例，请考虑：By contrast, as a working (but not particularly best-practice) example, consider:ssh somehost echo \"Hello" "World\"在这里，您要传递 ssh 两个参数： \ 的开头和结尾是第一个shell的文字（没有语法含义，因此 Hello 是第一个shell未引用）；但是仅在空白周围的 是语法上的，并告诉Shell保留该空白（因此引用了 space ）调用 ssh 时。因此，您将得到 { echo， \ Hello World\，NULL} ，它连接到字符串 echo Hello世界。Here, you're passing ssh two arguments: The \"s at the beginning and end are literal to the first shell (having no syntactical meaning, so the word Hello is to that first shell unquoted); but the "s just surrounding the whitespace is syntactical, and tells the shell to preserve that whitespace (so the spaces are quoted) when invoking ssh. Thus, you get { "echo", "\"Hello World\"", NULL }, which concatenates to the string echo "Hello World".最佳做法是通过仅传递单个字符串来避免此行为The best practice is to avoid this behavior by passing only a single string to ssh containing the entire script you want to run.# This worksssh somehost 'echo "Hello World"' ...如果要以编程方式生成该字符串，则可以这样操作（如果您知道您的远程shell是bash －即使bash-in- / bin / sh 模式也是安全的）：...if you want to generate that string programatically, you can do so as such (if you know that your remote shell is bash -- even bash-in-/bin/sh mode is safe):remote_command=( echo "Hello World" )printf -v remote_command_q '%q ' "${remote_command[@]}"ssh somehost "$remote_command_q"要使用任何符合POSIX的远程shell安全地执行此操作，请参见如何在脚本化的ssh命令中使用单引号和双引号To do that safely with any POSIX-compliant remote shell, see the Python-assisted answer in How to have simple and double quotes in a scripted ssh command 这篇关于当通过ssh传递时，为什么带引号的空格命令不起作用？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！ 上岸，阿里云！