On Fri, Jun 24, 2016 at 12:22:18AM -0400, Gene Heskett wrote:

> But why should a powerdown as unceremonious as pulling the plug, have 
> deleted /usr/bin/X?  It doesn't grok at this site.

File system corruption?

What file system do you have? If it is something with a journal (ext4, 
for example) I would be surprised. If it is something experimental or 
less reliable (btfs, reiserfs?) then I wouldn't be surprised.

All file systems can lose data if you interrupt them while updating the 
file system, but some are more resiliant than others. I tend to prefer 
the good old ext3 or ext4 standby over flashier, faster but less 
resiliant newer file systems, and older, unjournaled file systems like 
ext2.

Have a look inside /lost+found (assuming /usr/bin is in the / partition) 
and see if there's anything there. You may find all your X files, and 
more, given generic names. Or you may find nothing at all.


-- 
Steve