[ Thanks to dipinkrishna for this link.
]
“10.1.2 Dynamic Titles
screen has a shell-specific heuristic that is enabled by setting
the window’s name to search|name and arranging to have a null title
escape-sequence output as a part of your prompt. The search portion
specifies an end-of-prompt search string, while the name portion
specifies the default shell name for the window. If the name ends
in a `:’ screen will add what it believes to be the current command
running in the window to the end of the specified name (e.g.
name:cmd). Otherwise the current command name supersedes the shell
name while it is running.“Here’s how it works: you must modify your shell prompt to
output a null title-escape-sequence (ESC k ESC ) as a part of your
prompt. The last part of your prompt must be the same as the string
you specified for the search portion of the title.”