```ruby
require 'rbconfig'

CONFIG = Config::MAKEFILE_CONFIG


case ARGV[0]
when "archdir"
    puts Config::expand(CONFIG["archdir"])
when "lib"
    puts Config::expand(CONFIG["libdir"])
when "vendorarchdir"
    puts Config::expand(CONFIG["vendorarchdir"])
when "sitearchdir"
    puts Config::expand(CONFIG["sitearchdir"])
when "sitelib"
    puts Config::expand(CONFIG["sitedir"])
end

```

Use RbConfig instead of obsolete and deprecated Config (7, 17 May 2013)
user
```ruby
require 'rbconfig'

CONFIG = RbConfig::MAKEFILE_CONFIG


case ARGV[0]
when "archdir"
    puts RbConfig::expand(CONFIG["archdir"])
when "lib"
    puts RbConfig::expand(CONFIG["libdir"])
when "vendorarchdir"
    puts RbConfig::expand(CONFIG["vendorarchdir"])
when "sitearchdir"
    puts RbConfig::expand(CONFIG["sitearchdir"])
when "sitelib"
    puts RbConfig::expand(CONFIG["sitedir"])
end

```
assistant