To have screen start automatically upon login, add the following line to ~/.bash_profile.
Add the following to ~/.bashrc. This produces a message acknowledging screen is activated.
if [ "$TERM" = "screen" ]; then
echo "[ screen is activated ]"
Add the following to ~/.screenrc. It prevents screen from popping up its startup message; and defines the number of scrollback lines available.
Finally, to force xterm to start bash as a login shell (so that bash reads ~/.bash_profile), add the following line to ~/.Xresources. (This will have to be modified appropriately for other terminals.)
You can implement the changes to ~/.Xresources with the following command.