docs: def install_bash_completion(self, script_name=None, dest="~/.bashrc"):
          '''add line to activate bash_completion for given script_name into dest
  
          You can use this for letting the user install bash_completion::
  
              from argdeco import command, main
  
              @command("install-bash-completion",
                  arg('--dest', help="destination", default="~/.bashrc")
              )
              def install_bash_completion(dest):
                  main.install_bash_completion(dest=dest)
  
          '''
          if 'USERPROFILE' in os.environ and 'HOME' not in os.environ:
              os.environ['HOME'] = os.environ['USERPROFILE']
          dest = expanduser(dest)
          if script_name is None:
              script_name = sys.argv[0]
  
          self.uninstall_bash_completion(script_name=script_name, dest=dest)
          with open(dest, 'a') as f:
              f.write('eval "$(register-python-argcomplete %s)"\n' % script_name)