Rails 3，安裝pg gem時出錯

Question

試圖安裝pg gem我得到了下一個錯誤：

alex@ubuntu:~/RubymineProjects/Tiger Skills$ gem install pg
ERROR:  While executing gem ... (Gem::FilePermissionError)
You don't have write permissions into the /var/lib/gems/1.9.1 directory.
alex@ubuntu:~/RubymineProjects/Tiger Skills$ sudo gem install pg
Building native extensions.  This could take a while...
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

    /usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from extconf.rb:2:in `<main>'


Gem files will remain installed in /var/lib/gems/1.9.1/gems/pg-0.15.1 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/pg-0.15.1/ext/gem_make.out

gem_make.out文件：

/usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from extconf.rb:2:in `<main>'

已經嘗試解決使用問題

$ sudo apt-get install postgresql-client libpq5 libpq-dev

然后：

$ sudo gem install pg

Answer 1

那是因為您沒有為目錄設置寫權限，請嘗試：

   chmod +777 /var/lib/gems/1.9.1

Answer 2

這有助於我：

sudo apt-get install rails 

Answer 3

您需要安裝Ruby包的-dev部分。 就像是：

sudo apt-get install ruby1.9-dev

應該為您提供編譯二進制擴展所需的Ruby部分。

祝好運！

Answer 4

我得到了幾乎相同的問題。
我用它來解決它。

$rvmsudo gem install pg