Ruby which-like command (rwhich)

calendar Feb 6, 2011

Here is a Ruby script to find libraries (like the ones used with require). It is like the Unix which tool.

There is a similar tool here, but this script doesn’t attempt to load the library (which sometimes causes load errors), and this script also locates gem libraries.

#!/usr/bin/env ruby

require ‘pathname’


EXTENSIONS = %w(.rb .so .o .dll .dylib .class)
def which(file)
return file if Pathname.new(file).absolute?
if EXTENSIONS.any? { |ext| file.end_with?(ext) }
search = [ file ]
else
search = EXTENSIONS.map { |ext| file + ext }
end
$LOAD_PATH.each do |path|
res = search.map { |f| File.join(path, f) }.find { |f|
File.exist?(f)
}
next if res.nil?
puts res
exit
end
return nil
end


file = ARGV[0]
puts “Usage: #{File.filename($0)} [library]” unless file
res = which(file)


require ‘rubygems’
if spec = Gem.searcher.find(file)
Gem.activate(spec.name, “= #{spec.version}")
res = which(file)
end


STDERR.puts “#{file}: Library not found.”
exit 1