A couple of years ago, tchrist had an idea to reimplement basic Unix commands in Perl. Lots of people wrote one tool or utility and contributed it to Tom's Perl Power Tools (ppt) project.
According to the project web page, development appears to have stopped sometime in 1999.
The recent release of Ruby 1.8.0 has rekindled this idea. At the bottom of the release summary, Why describes the use of ruby -run:
ruby -run -e cp -- [OPTION] SOURCE DEST ruby -run -e ln -- [OPTION] TARGET LINK_NAME ruby -run -e mv -- [OPTION] SOURCE DEST ruby -run -e rm -- [OPTION] FILE ruby -run -e mkdir -- [OPTION] DIRS ruby -run -e rmdir -- [OPTION] DIRS ruby -run -e install -- [OPTION] SOURCE DEST ruby -run -e chmod -- [OPTION] OCTAL-MODE FILE ruby -run -e touch -- [OPTION] FILE
Personally, it's not replaced Unix till they've written troff.
-Dom
