Scala:在 sbt 中更改文件夹 [英] Scala: change folder inside sbt

问题描述

我有一个多模块的 sbt 项目，我想在我的项目的根文件夹中运行一个命令；因此我需要做 cd ../.. .

I have a multi-module sbt project and I want to run a command in the root folder of my project; hence I need to do cd ../.. .

我试过了

import sys.process._
"cd ../..".! 

但我得到以下信息:

java.io.IOException: Cannot run program "cd": error=2, No such file or directory
  at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
  at scala.sys.process.ProcessBuilderImpl$Simple.run(ProcessBuilderImpl.scala:69)
  at scala.sys.process.ProcessBuilderImpl$AbstractBuilder.run(ProcessBuilderImpl.scala:98)
  at scala.sys.process.ProcessBuilderImpl$AbstractBuilder.$bang(ProcessBuilderImpl.scala:112)

推荐答案

cd 实际上并不是一个程序.它是一个 shell 内部的，它告诉 shell chdir 系统调用.Java 甚至没有使整个 jvm 更改其 cwd(当前工作目录)的功能(请参阅 在 Java 中更改当前工作目录?) -- 对于 Java 文件访问，有 user.dir 属性，但这只是 Java 函数看起来的一个变量在.

cd is not actually a program. It's a shell-internal that tells the shell to the chdir system call. Java doesn't even have a function to make the entire jvm to change its cwd (current working directory) (see Changing the current working directory in Java?) -- for Java file access, there is the user.dir property, but that's just a variable that Java functions look at.

一个选项是执行 sh -c "..."，在 fork 进程中改变目录，如下所示:

One option is executing sh -c "...", changing the directory within the forked process, like so:

import sys.process._
val cmd = "whatever you wanted to run"
s"sh -c 'cd ../..; $cmd'".!

但最好还是使用 http://www.scala-lang.org/files/archive/api/current/index.html#scala.sys.process.Process$ 工厂同时采用 命令 和一个 cwd:

But better still would be to use the http://www.scala-lang.org/files/archive/api/current/index.html#scala.sys.process.Process$ factories that take both a command and a cwd:

scala.sys.process.Process("your command here", new java.io.File("/some/dir"))

要使用相对目录，您可能需要从 user.dir 和../.."创建 cwd 和/或执行类似 如何在java中定义相对路径

To use a relative dir, you might need to create the cwd from user.dir and "../.." and/or do something like How to define a relative path in java

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