周海漢 2010.7.12
ubuntu 10.04 安裝ruby & rails時遇到問題，如下：
`require': no such file to load -- mkmf (LoadError)
安裝過程：
安裝ruby1.9.1
zhouhh@zhh64:~$ sudo apt-get install ruby1.9.1-full
zhouhh@zhh64:~$ sudo apt-get install rubygems1.9.1
gem 是ruby 的自動打包安裝工具
安裝mysql server和客戶端
zhouhh@zhh64:~$ sudo apt-get install mysql-server-5.1 php5-mysql libmysqlclient-dev libmysqld-dev mysql-client-5.1
但用gem安裝mysql時一直報錯
zhouhh@zhh64:~$ sudo gem install mysql
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.
/usr/bin/ruby1.9.1 extconf.rb
extconf.rb:10:in `require': no such file to load -- mkmf (LoadError)
from extconf.rb:10:in `<main>'
Gem files will remain installed in /var/lib/gems/1.9.1/gems/mysql-2.8.1 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/mysql-2.8.1/ext/mysql_api/gem_make.out
找了很多資料，都說是ruby-dev沒安裝，但其實是安裝了的。
後面發現是ruby安裝了兩個版本，引起問題
zhouhh@zhh64:~$ ruby -v
ruby 1.8.7 (2010-01-10 patchlevel 249) [x86_64-linux]
直接執行ruby，是系統自帶的，1.8.7
刪除ruby1.8
zhouhh@zhh64:~$ sudo apt-get remove ruby1.8
再安裝就好了
zhouhh@zhh64:~$ sudo gem install mysql
Building native extensions. This could take a while...
Successfully installed mysql-2.8.1
1 gem installed
Installing ri documentation for mysql-2.8.1...
Updating class cache with 2469 classes...
Installing RDoc documentation for mysql-2.8.1...
安裝rails
zhouhh@zhh64:~$ sudo gem install rails --include-dependencies
INFO: `gem install -y` is now default and will be removed
INFO: use --ignore-dependencies to install only the gems you list
Successfully installed rake-0.8.7
Successfully installed activesupport-2.3.8
Successfully installed activerecord-2.3.8
Successfully installed rack-1.1.0
Successfully installed actionpack-2.3.8
Successfully installed actionmailer-2.3.8
Successfully installed activeresource-2.3.8
Successfully installed rails-2.3.8
8 gems installed
Installing ri documentation for rake-0.8.7...
Installing ri documentation for activesupport-2.3.8...
Installing ri documentation for activerecord-2.3.8...
Installing ri documentation for rack-1.1.0...
Installing ri documentation for actionpack-2.3.8...
Installing ri documentation for actionmailer-2.3.8...
Installing ri documentation for activeresource-2.3.8...
Installing ri documentation for rails-2.3.8...
Updating class cache with 0 classes...
Installing RDoc documentation for rake-0.8.7...
Installing RDoc documentation for activesupport-2.3.8...
測試ruby
zhouhh@zhh64:~$ irb
bash: /usr/bin/irb: 沒有那個文件或目錄
zhouhh@zhh64:~$ irb1.9.1
irb(main):001:0> 3+2
=> 5