The intended use of this script is to set up several Yohkoh environmentals which control IDL startup. These include setting defaults for X windows startup, message of the day display, fast startup, etc. Use the ``gen'' version of the file ($ys/gen/setup/setup_ysenv) as a template and for some discussion of options. The site manager may use the site version of this file to change the distributed defaults. If a user has a file with this name in the HOME directory, it will be executed to supercede or supplement the default and site environment. Since it is just a script file which gets automatically executed during the Yohkoh startup, sophisticated users may discover additional uses.