Linux 我可以在 UNIX shell 中执行嵌套或链式命令吗？
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Can I execute nested or chained commands in UNIX shell?
提问by Osama Ahmad
Can I execute command within another command in UNIX shells?
我可以在 UNIX shell 中的另一个命令中执行命令吗？
If impossible, can I use the output of the previous command as the input of next command, as in:
如果不可能，我可以使用上一个命令的输出作为下一个命令的输入，例如：
command xthen command y,
command x那么command y，
where in command yI want use the output of command x?
command y我想在哪里使用command x?
采纳答案by Jim Nutt
What exactly are you trying to do? It's not clear from the commands you are executing. Perhaps if you describe what you're looking for we can point you in the right direction. If you want to execute a command over a range of file (or directory) names returned by the "find" command, Colin is correct, you need to look at the "-exec" option of "find". If you're looking to execute a command over a bunch of arguments listed in a file or coming from stdin, you need to check out the "xargs" commands. If you want to put the output of a single command on to the command line of another command, then using "$(command)" (or 'command' [replace the ' with a backquote]) will do the job. There's a lot of ways to do this, but without knowing what it is you're trying it's hard to be more helpful.
你到底想做什么？从您正在执行的命令中不清楚。也许如果您描述了您正在寻找的内容，我们可以为您指明正确的方向。如果要对“find”命令返回的一系列文件（或目录）名称执行命令，Colin 是正确的，则需要查看“find”的“-exec”选项。如果您希望对文件中列出的或来自标准输入的一堆参数执行命令，则需要查看“xargs”命令。如果您想将单个命令的输出放到另一个命令的命令行上，那么使用“$(command)”（或“command”[用反引号替换 ']）就可以完成这项工作。有很多方法可以做到这一点，但在不知道它是什么的情况下，你正在尝试它”
回答by Colin Hebert
You can use the backquotes for this.
您可以为此使用反引号。
For example this will cat the file.txt
例如，这将 cat file.txt
cat `echo file.txt`
cat `echo file.txt`
And this will print the date
这将打印日期
echo the date is `date`
echo 日期是`date`
The code between back-quotes will be executed and be replaced by its result.
反引号之间的代码将被执行并被其结果替换。
回答by codaddict
You can do something like;
你可以做类似的事情；
x=$(grep $(dirname "$path") file)
here dirname "$path"will run first and its result will be substituted and then grep will run, searching for the result of dirnamein the file
这里dirname "$path"将首先运行，它的结果将被替换，然后grep的运行，搜索结果dirname中file
