Through an incrediby boneheaded mistake, I have deleted my /usr/bin directory on my MacBook. Fortunately it only had a small number of programs that weren't there by default. Also, most of the GUI seems to run just fine without the bin directory, and the computer boots. But I do not know how to recover the directory. My best guess at this point is to solicit people I know who use macs to give me their /usr/bin directories. Worst case, I could reinstall the whole OS. But before I try that, is there any other way that I can get this directory?