It seems that the installation of Ruby through rvm is not as easy as I think. The following two commands have failed.

$ rvm pkg install iconv

$ rvm install 1.9.2 -C --with-openssl-dir=$HOME/.rvm/usr,--with-iconv-dir=$HOME/.rvm/usr

The Octopress official documentation as well as a Chinese page have those commands. Luckily, Krish's approach works on my computer.

I created this post to see if this affects UltraBlog.vim.

Posted via UltraBlog.vim.