Just solved a few “obscure” problems and I’m posting them.

Dependencies

Optional (but you would really like to install them) dependencies are:

• OpenSSL (Debian-based package: libssl-dev)
• readline (Debian-based package: libreadline5-dev [ruby1.8] | libreadline6-dev [ruby1.9]. For Ruby1.8, you must install readline 5, otherwise you’ll get a damn slow prompt)
• zlib (Debian-based package: zlib1g-dev)

Here are a few compeling motives on why you’d really like to get them:

• No SSL means no ‘net/https’ and no HTTPs for ‘open-uri’
• No readline means you can’t hit ‘up arrow’ on IRB and get the previous command (no command history)
• No zlib means you can’t install a gem

Long story short, install ‘em. And get the right versions.