# File lib/librarian/posix.rb, line 16 def which(cmd) exts = ENV["PATHEXT"] ? ENV["PATHEXT"].split(';') : [''] ENV["PATH"].split(File::PATH_SEPARATOR).each do |path| path = File.expand_path(path) exts.each do |ext| exe = File.join(path, cmd + ext) return exe if File.file?(exe) && File.executable?(exe) end end nil end