我用 ubuntu 系统，刚刚在安装 pg 时报错；如下信息，我在网上搜索了一下 找到http://effectif.com/databases/installing-pg-gem-on-mac 这个方法，我也找到了/usr/lib/postgresql/9.1/bin 的目录，也用了 PATH=$PATH:/usr/lib/postgresql/9.1/bin sudo gem install pg 还是不行，求助！
第一次报错
shin@ubuntu:~/rails-project/jiefu$ gem install pg
Building native extensions. This could take a while...
ERROR: Error installing pg:
ERROR: Failed to build gem native extension.
/home/shin/.rvm/rubies/ruby-1.9.2-p320/bin/ruby extconf.rb
checking for pg_config... yes
Using config values from /usr/bin/pg_config
You need to install postgresql-server-dev-X.Y for building a server-side extension or libpq-dev for building a client-side application.
You need to install postgresql-server-dev-X.Y for building a server-side extension or libpq-dev for building a client-side application.
checking for libpq-fe.h... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/home/shin/.rvm/rubies/ruby-1.9.2-p320/bin/ruby
--with-pg
--without-pg
--with-pg-dir
--without-pg-dir
--with-pg-include
--without-pg-include=${pg-dir}/include
--with-pg-lib
--without-pg-lib=${pg-dir}/lib
--with-pg-config
--without-pg-config
--with-pg_config
--without-pg_config
/home/shin/.rvm/rubies/ruby-1.9.2-p320/lib/ruby/1.9.1/mkmf.rb:368:in `try_do': The complier failed to generate an executable file. (RuntimeError)
You have to install development tools first.
第二次报错
PATH=$PATH:/usr/lib/postgresql/9.1/bin 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-0.14.0 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/pg-0.14.0/ext/gem_make.out
You need to install postgresql-server-dev-X.Y for building a server-side extension or libpq-dev
以前没有用过 linux 的时候，就知道它的命令行很吓人，就怕没有 windows 的界面，就怕 linux 不是普通人用的，等等。 其实被误导了，不过主要怪自己没有亲自尝试。 这一年用下来，才发现，linux 的提示很多时候比 windows 还要好。 以前总觉得.NET 有 msdn，很强大。用来 python，ruby 才发现，python 的文档，ruby 的文档，比 msdn 要好不知道多少倍，而且很实用，介绍很详细。给出的示例代码，很快就可以看明白。 不像 msdn，看似很多东西，但是很多都是没有用的代码，不相关的，一大丢，很难找到你想要的介绍。 哈哈~~~
