Q:

SHA1 error when using brew install

More specifically, I was using homebrew to install MySQL, and I got this error:
Error: SHA1 mismatch  
Expected: f218ed64ce6e7a5d3670acdd6a18e5ed95421d1f  
Got: 3a57f6f44186e0dba34ef8b8fb4a9047e9e5d8a3  
Archive: /Users/rdp/Library/Caches/Homebrew/cmake-2.8.7.bottle.tar.gz  
(To retry an incomplete download, remove the file above.)

A:

Everything worked after I ran brew update.

A:

Incase the brew update fails, try the following
cd `brew --prefix`
git remote add origin https://github.com/Homebrew/homebrew
git fetch origin
git reset --hard origin/master

