If you try to install Undertale on Linux using Wine you’ll probably encounter the error message “Cabinet is not valid”.

Others suggest working around this problem by booting to Windows and getting necessary files from Windows, but there is no need to put your effort in such nuisance.

The Undertale installer is merely a self extracting archive. If you rename the extension from exe to zip you’ll be able to open it in your file explorer and extract it right away.

Just extract all files to a folder and start undertale.exe