The attached patch: 
 
- defines that scripts are sub-class-of application/x-executable, so that it 
becomes easy to check if something is executable (all it needs is to inherit 
x-executable and have +x permissions) 
 
- merges text/x-ksh into application/x-shellscript (does anyone really need a 
separate mimetype for this? If so, then it should be defined as application/x-* 
for consistency and it should be a subclass of application/x-shellscript) 
 
- moves the magic for csh scripts to the existing application/x-csh mimetype, 
and defines that it's a subtype of application/x-shellscript 
 
- defines that the script types are also text/plain. Many more types in the 
database are subclasses of text/plain, I'll file another report for that.