pry(main)> show-command ".<shell command>"

From: /Users/john/ruby/projects/pry/lib/pry/default_commands/shell.rb @ line 6:
Number of lines: 15

command(/\.(.*)/, "All text following a '.' is forwarded to the shell.", :listing => ".<shell command>", :use_prefix => false) do |cmd|
  if cmd =~ /^cd\s+(.+)/i
    dest = $1
    begin
      Dir.chdir File.expand_path(dest)
    rescue Errno::ENOENT
      output.puts "No such directory: #{dest}"
    end

  else
    if !system(cmd)
      output.puts "Error: there was a problem executing system command: #{cmd}"
    end
  end
end
pry(main)>