docs: def cmd_ssh(options):
      """Connect to the specified instance via ssh.
  
      Finds instances that match the user specified args that are also
      in the 'running' state.  The target instance is determined, the
      required connection information is retreived (IP, key and ssh
      user-name), then an 'ssh' connection is made to the instance.
  
      Args:
          options (object): contains args and data from parser
  
      """
      import os
      import subprocess
      from os.path import expanduser
      options.inst_state = "running"
      (i_info, param_str) = gather_data(options)
      (tar_inst, tar_idx) = determine_inst(i_info, param_str, options.command)
      home_dir = expanduser("~")
      if options.user is None:
          tar_aminame = awsc.get_one_aminame(i_info[tar_idx]['ami'])
          options.user = cmd_ssh_user(tar_aminame,
                                      i_info[tar_idx]['tag']['Name'])
      else:
          debg.dprint("LoginUser set by user: ", options.user)
      os_spec = {"nt": ["powershell plink", "\\", "ppk"]}
      c_itm = os_spec.get(os.name, ["ssh", "/", "pem"])
      cmd_ssh_run = c_itm[0]
      if not options.nopem:
          cmd_ssh_run += (" -i {0}{1}.aws{1}{2}.{3}".
                          format(home_dir, c_itm[1], i_info[tar_idx]['ssh_key'],
                                 c_itm[2]))
      else:
          debg.dprint("Connect string: ", "ssh {}@{}".
                      format(options.user, i_info[tar_idx]['pub_dns_name']))
      cmd_ssh_run += " {0}@{1}".format(options.user,
                                       i_info[tar_idx]['pub_dns_name'])
      print(cmd_ssh_run)
      subprocess.call(cmd_ssh_run, shell=True)