在 ruby 脚本中更改目录？
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To change directory inside a ruby script?
提问by never_had_a_name
I want to create a new rails application and fire up the rails server for that application, everything from a ruby script.
我想创建一个新的 rails 应用程序并为该应用程序启动 rails 服务器，一切都来自 ruby 脚本。
My code look like this:
我的代码如下所示：
#!/usr/bin/env ruby
system "rails new my_app"
system "cd my_app"
system "rails server &"
However, when running "rails server &" the path is not in the my_app folder, but in the parent folder.
但是，当运行“rails server &”时，路径不在 my_app 文件夹中，而是在父文件夹中。
Is there a way to change directory inside a script so that i can run "rails server", "rake about" and "rake db:migrate" for that new application?
有没有办法更改脚本内的目录，以便我可以为该新应用程序运行“rails server”、“rake about”和“rake db:migrate”？
All work around tips would be appreciated.
所有解决技巧的工作将不胜感激。
回答by taw
Don't listen to them, Dir.chdir("dir")will probably do the wrong thing. What you almost always want is to limit change to a particular context, without affecting the rest of the program like this:
不要听他们的，Dir.chdir("dir")可能会做错事。您几乎总是想要的是将更改限制在特定的上下文中，而不像这样影响程序的其余部分：
#!/usr/bin/env ruby
system "rails new my_app"
Dir.chdir("my_app") do
system "rails server &"
end
# back where we were, even with exception or whatever
回答by wondersz1
system supports :chdir argument that allows you to specify its working directory:
系统支持 :chdir 参数，允许您指定其工作目录：
system("echo Test; pwd", chdir: '/tmp')
outputs '/tmp'
输出'/tmp'
回答by user402987
Use Dir.chdir("[aString]")
使用Dir.chdir("[aString]")
回答by Gaurav Manchanda
Why can't you just do it like this:
为什么你不能这样做：
#!/usr/bin/env ruby
system 'rails new myapp && cd myapp && rails server &'
回答by itsnikolay
The following lines have the same output:
以下几行具有相同的输出：
puts Dir.chdir("/tmp") { IO.popen("ls -la") { |io| io.read } }
puts IO.popen(["ls", "-la", "/tmp"]).read
puts IO.popen("ls -la /tmp").read
# drwxrwxrwt 25 root root 16384 июля 23 01:17 .
# drwxr-xr-x 22 root root 4096 июля 22 13:36 ..
# drwxrwxr-x 12 itsnikolay itsnikolay 4096 июля 19 17:14 app_template
# drwx------ 2 itsnikolay itsnikolay 4096 июля 21 15:04 .com.google.Chrome.dThb8f
# drwx------ 2 itsnikolay itsnikolay 4096 июля 18 20:55 .com.google.Chrome.FGDBGc
also you can run rails and create an application (this can be helpful in rspec tests and etc.):
你也可以运行 rails 并创建一个应用程序（这在 rspec 测试等中很有帮助）：
IO.popen("cd /tmp/ && rails new test_app").read
and ever you can run a rails server ;)
并且您可以运行 Rails 服务器；)
