echo <string> - Echo the string to the screen.
redirect_output <filename> - Append all Twill output to the given file.
reset_output - Display all output to the screen.
save_html [<filename>] - Save the current page's HTML to a file. If no filename is given, derive the filename from the URL.
show - Show the current page's HTML.
showlinks - Show all of the links on the current page.
showforms - Show all of the forms on the current page.
showhistory - Show the browser history.