Homebrew

Basics

choose specific version of installed package

% brew info imagemagick
imagemagick: stable 6.9.0-3 (bottled), HEAD
http://www.imagemagick.org
/usr/local/Cellar/imagemagick/6.8.8-9 (1429 files, 21M)
/usr/local/Cellar/imagemagick/6.8.9-1 (1432 files, 22M)
/usr/local/Cellar/imagemagick/6.9.0-3 (1440 files, 22M) *

set active version

% brew switch imagemagick 6.8.9-9

Troubleshooting

brew doctor

/usr/local is not writable.

sudo chown -R $USER:admin /usr/local/include