Rcmd install mypkg
Requiring Perl script names to be specified in a case-sensitive way doesn't affect the R build process, but it does mean that a script written on Windows is slightly more likely to work when someone runs it on another platform. There's an "install" command in at least some flavours of Unix that would be invoked instead of R's INSTALL script if you said "R CMD install" on one of those platforms, and that's not a good thing.
Will this be changing on OS X too? My version of 2006-09-20 r39433 accepts either upper or lower case commands. Hadley