libyaml / psych / rvm / zlib issues

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Every time I set up a new Ubuntu instance for Ruby development, I run into the same problem. After installing rvm, when I try to install a gem it complains about not being able to find psych for yaml and not finding zlib. I can't seem to get the hang of this. As usual, I found a number of different solutions online, and each of them solved the problem for some people and not for others. FWIW, this is what corrected the problem for me on a fresh instance of Ubuntu 12.10:

sudo apt-get install zlib1g-dev
sudo apt-get install libyaml-dev
rvm reinstall 1.9.3

Maybe this will help you if you're having a similar problem.

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Getting Instiki wiki working on Ubuntu 11.04

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I started by copying my backup of the whole directory .wiki from an external drive to /home/.wiki.
Then I ran the following commands:

rvm gem install bundler
sudo apt-get install
    libxml2-dev
    libxslt1-dev
    sqlite3
    libsqlite3-dev
cd .wiki
bundle

Bundler installed other components Instiki uses, including nokogiri, rubyzip, and sqlite3-ruby.

Instiki did not start, and reported this error:

/home/dave/.rvm/rubies/ruby-1.9.2-p180/lib
    /ruby/1.9.1/psych.rb:148:in `parse': 
    couldn't parse YAML at line 18 column 14 (Psych::SyntaxError)

I found an explanation and workaround by vicvega on
Stack Overflow. I added the lines

require 'yaml'
YAML::ENGINE.yamler= 'syck'

at the top of Instiki's config/boot.rb file (just above the comment that reads, "Don't change this file!"), and Instiki started up clean. In a nutshell, the problem was that bundler uses psych as the default yaml parser, psych is not compatible with rails, and Instiki is a rails app.

In .bash_aliases I added a line to start the wiki conveniently:

alias wiki=~/.wiki/instiki

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