Get IP on Linux

Today I needed to get the ip address as part of script to configure the "/etc/hosts" file. The command to get the IP is a one line command:

$ ifconfig | grep 'inet addr:' | grep -v '127.0.0.1' | cut -d: -f2 | awk '{ print $1 }'

Thats all it takes to get the IP address(es) of the current interfaces excluding the loop back adapter. Other variants of *nix and windows may require different commands.

Get rpm and dependencies

On RHEL/Centos you need to install "yum-utils" first. $ sudo yum install yum-utils Then you can download an rpm and its depdencies by doing the following: $ sudo yumdownloader --resolve <rpm name> Then, you can transport them to another computer with a USB drive.

Add RSpec

I need to add the rspec gem to my ruby project. How do I do that?  Can I do this from the command line or do I need to open a file? Looks like I need to open my "gemspec" file and add the line: spec.add_development_dependency "rspec" Then, I can install the gem through bundler from the command line: $ bundle install Next, add a directory structure and spec files. [project]/spec/spec_helper.rb # Reference code in ../lib [project]/spec/[gem name]/actual_spec.rb # Relative reference to ../spec_helper.rb Now you should be able to run rspec from the command line: $ bundle exec rspec actual_spec.rb