如何使节点child_process连续执行 [英] how do I make node child_process exec continuously

问题描述

如何连续 exec ？例如 cd 后的 ls 吗？

How to exec continuously? e.g. ls after cd?

我尝试过

exec = require('child_process').exec;
exec('cd ~/', 
  function(){
    exec('ls'),
    function(err, stdout, stderr){
      console.log(stdout); // this logs current dir but not ~/'s
    }
  }
)

exec('cd ~/').exec('ls', function(err, stdout, stderr){
  console.log(stdout);
})//this also fails because first exec returns a ChildProcess Object but not itself.

推荐答案

无法执行此操作，因为exec和spawn创建一个新的过程。但是有一种方法可以模拟这种情况。您可以使用exec启动一个进程并同时执行多个命令：
在命令行中，如果要在同一行执行3个命令，则应编写：

It is not possible to do this because exec and spawn creates a new process. But there is a way to simulate this. You can start a process with exec and execute multiple commands in the same time: In the command line if you want to execute 3 commands on the same line you would write:

cmd1 & cmd2 & cmd3

因此，所有3条命令都在同一进程中运行，并且可以访问由前一个命令修改的上下文执行的命令。
让我们举一个例子，您要执行cd ../，然后执行dir并查看上一个目录列表。
您应该在cmd中写：

So, all 3 commands run in the same process and have access to the context modified by the previous executed commands. Let's take your example, you want to execute cd ../ and after that to execute dir and to view the previous directory list. In cmd you shoud write:

cd../ & dir

从节点js中，您可以使用exec启动一个进程，并告诉它启动另一个节点实例，将评估内联脚本：

From node js you can start a process with exec and to tell it to start another node instance that will evaluate an inline script:

var exec = require('child_process').exec;
var script = "var exec = require('child_process').exec;exec('dir',function(e,d,er){console.log(d);});";
script = '"'+script+'"';//enclose the inline script with "" because it contains spaces
var cmd2 = 'node -e '+script;
var cd = exec('cd ../ &'+cmd2,function(err,stdout,strerr)
{
    console.log(stdout);//this would work
})

如果您只想更改当前目录，则应查阅有关文档 http://nodejs.org/api/child_process.html#child_process_child_process_exec_command_options_callback

If you just want to change the current directory you should check the documentation about it http://nodejs.org/api/child_process.html#child_process_child_process_exec_command_options_callback

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