我搜索了 Stack Overflow 并阅读了几个网页，并尝试了使用 Macports 和 HomeBrew 的 Nokogiri 网站上的方法，但仍然一无所获。
gem install nokogiri
ERROR: While executing gem ... (Errno::EACCES)
Permission denied - /Library/Ruby/Gems/1.8/gems/nokogiri-1.5.9/.autotest
所以，我不得不使用 sudo 命令来查看是否可以安装它。
sudo gem install nokogiri
Building native extensions. This could take a while...
ERROR: Error installing nokogiri:
ERROR: Failed to build gem native extension.
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
checking for libxml/parser.h... yes
checking for libxslt/xslt.h... yes
checking for libexslt/exslt.h... yes
checking for iconv_open() in iconv.h... no
checking for iconv_open() in -liconv... no
checking for iconv_open() in -liconv... no
checking for libiconv_open() in iconv.h... no
checking for libiconv_open() in -liconv... no
checking for libiconv_open() in -liconv... no
-----
libiconv is missing. please visit
http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing
dependencies.
-----
*** 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
--without-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=/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
--with-zlib-dir
--without-zlib-dir
--with-zlib-include
--without-zlib-include=${zlib-dir}/include
--with-zlib-lib
--without-zlib-lib=${zlib-dir}/lib
--with-iconv-dir
--without-iconv-dir
--with-iconv-include
--without-iconv-include=${iconv-dir}/include
--with-iconv-lib
--without-iconv-lib=${iconv-dir}/lib
--with-xml2-dir
--without-xml2-dir
--with-xml2-include
--without-xml2-include=${xml2-dir}/include
--with-xml2-lib
--without-xml2-lib=${xml2-dir}/lib
--with-xslt-dir
--without-xslt-dir
--with-xslt-include
--without-xslt-include=${xslt-dir}/include
--with-xslt-lib
--without-xslt-lib=${xslt-dir}/lib
--with-libxslt-config
--without-libxslt-config
--with-pkg-config
--without-pkg-config
--with-libxml-2.0-config
--without-libxml-2.0-config
--with-pkg-config
--without-pkg-config
--with-libiconv-config
--without-libiconv-config
--with-pkg-config
--without-pkg-config
--with-iconvlib
--without-iconvlib
--with-iconvlib
--without-iconvlib
--with-iconvlib
--without-iconvlib
--with-iconvlib
--without-iconvlib
Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/nokogiri-1.5.9 for
inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/nokogiri-1.5.9/ext/nokogiri/gem_make.out
看起来我的 Mac 中包含的 libxml 和 libexslt 正在工作，而 libiconv 没有。只是为了给出观点，我最初试图使用 RSpec，但是水豚有错误，这是不可能的，因为 nokogiri 不起作用。
感谢任何有建议的人。就像我说的，Homebrew 没有用——而且我不打算重新安装操作系统，因为安装 Rails 3 本身对我来说很烦人。