I have these 4 lines of code in a script file on my netbook. It changes the
screen size of the external monitor and turns off the netbook lcd. This is in a
script that runs at startup. What I would like is to modify this script or have
another script call this script. The new code would ask if you wanted to make
these changes and wait may be 10 seconds and take a default or use a yes or no
answer. Something like grub does on multi-boot systems.

There must be an easy way to do this but so far I have failed to come up with a
soultion.

This is the 4 lines of code that changes the screen
xrandr --newmode "1680x1050" 146.25 1680 1784 1960 2240 1050 1053 1059 1089
-hsync +vsync
xrandr --addmode VGA1 "1680x1050"
xrandr --output VGA1 --mode "1680x1050"
xrandr --output LVDS1 --off