Fun with RVM

I typically work with jRuby.  I don't have "rvm use jruby" in my bash scripts,  but I might as well.

I wanted to install awestruct this morning.  I wanted to use C Ruby, or MRI.

The frst step for using awestruct is of course to install awestruct, gem install awestruct.

I got the following :

ERROR:  Loading command: install (LoadError)
    no such file to load -- zlib
ERROR:  While executing gem ... (NameError)
    uninitialized constant Gem::Commands::InstallCommand

  
I tried to install zlib with RVM :
rvm pkg install zlib

Unfortunately that didn't work:
/home/jeremy/.rvm/scripts/functions/pkg: line 52: cd: /home/jeremy/.rvm/src/zlib-1.2.6: No such file or directory
Configuring zlib in /home/jeremy/.rvm/src/zlib-1.2.6.
Error running ' ./configure --prefix="/home/jeremy/.rvm/usr"  ', please read /home/jeremy/.rvm/log/zlib/configure.log
Compiling zlib in /home/jeremy/.rvm/src/zlib-1.2.6.
Error running 'make ', please read /home/jeremy/.rvm/log/zlib/make.log

I tried the quick fix from the RVM site, https://rvm.io/packages/zlib/.
Reinstalled Ruby with :
rvm reinstall 1.9.2
rvm use 1.9.2
gem install awestruct

And back to work.

How to enable a datasource using the JBoss CLI

data-source enable --name=DATASOURCE-NAME

How to shut down JBoss EAP6 / AS7 from the CLI

From the JBOSS_HOME/bin run the following :

./jboss-cli.sh --connect command=:shutdown

Changing a symbolic link in Linux

Symbolic links are great.

I need to swap out local Maven repositories for the project I'm working on.  I created a symbolic link, "maven_repo" in my home directory that points the current local Maven repo.  When it came time to change the "maven_repo" link I realized that changing a symbolic link to a directory requires an extra command :

ln -sfn DESTINATION_DIRECTORY LINK_NAME

It wasn't so obvious from the man page.  This blog post saved me a ton of time.

Gnome Shell shortcuts

There is an excellent cheat sheet/post about Gnome Shell at (go figure) gnome.org, http://live.gnome.org/GnomeShell/CheatSheet

I'll repost a quick summary here :

• System (Windows) key: Switch between overview and desktop
• Alt+F1: Switch between overview and desktop
• Alt+F2: Pop up command dialog
• Alt+Tab: Pop up application switcher
• Alt+Shift+Tab: Cycle in reverse direction in the application switcher
• Alt+[key above Tab]: Switch between windows of the same application in Alt+Tab
• Ctrl+Alt+Tab: Pop up accessibility switcher
• Ctrl+Shift+Alt+R: Start and end screencast recording
• Ctrl+Alt+Up/Down arrow: Switch between workspaces
• Ctrl+Alt+Shift+Up/Down arrow: Move the current window to a different workspace
• Ctrl+Enter: Launch a shell command in a new Terminal window

Fedora 16, gnome-shell and rvm

I recently upgraded to Fedora 16.  There's lots to like.  There are some things that are annoying.

I found a couple of new oddities this evening after installing rvm.

First, rvm requires gcc, and gcc has to be installed.  I sort of assumed that gcc would have already been around.  Anyway,

sudo yum install gcc

did the trick. Second, after

• installing rvm
• logging out
• logging back in
• installing Ruby 1.9.2
• installing the latest JRuby
• logging out
• logging back in

I ran :

rvm use jruby

I got :

RVM is not a function, selecting rubies with 'rvm use ...' will not work.

Huh?

There is of course an entry on the rvm site.  It's some gnome-terminal weirdness.  I was launching the terminal with Alt + F2.

RVM, jRuby, ActiveRecord::ConnectionNotEstablished, and PostgreSQL

I generated a new Rails 3 app with a PostgreSQL backend.  I was using the latest jRuby.

I started the server and got :

ActiveRecord::ConnectionNotEstablished

That was annoying.
I connected to the database from the command line and from another tool.
I ran rails console and got the following :

ArgumentError: syntax error on line 42, col 0: `'
                    load at org/yecht/ruby/YParser.java:152
                    load at /home/[USER NAME]/.rvm/rubies/jruby-1.6.5/lib/ruby/1.8/yaml.rb:134
  database_configuration at /home/[USER NAME]/.rvm/gems/jruby-1.6.5/gems/railties-3.2.1/lib/rails/application/configuration.rb:115

Taking a look at yaml.rb line 134 clued me in that I was using the wrong jRuby compatibility.

RVM to the rescue.  RVM is just pure goodness.  It really makes switching rubies a breeze.

The executive summary is that RVM makes it easy to run multiple versions of Ruby and/or Ruby gems.  To use jRuby :

rvm use jRuby

It even makes it easy to set jRuby's version compatibility.  RVM  allows you to specify hooks to run after its' methods.

jRuby 1.6.x has 1.8 and 1.9 Ruby compatibility.  To use 1.9 just add an "after_use" hook (this is detailed on the RVM site).