OpenCVの2がほしい
まず、パッケージを探す。
$ brew search opencv
==> Formulae
opencv opencv@2 opencv@3
見つけたので、opencv@2の詳細を確認しておく。
$ brew info opencv@2
opencv@2: stable 2.4.13.7 (bottled) [keg-only]
Open source computer vision library
https://opencv.org/
Not installed
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/opencv@2.rb
==> Dependencies
Build: cmake ✘, pkg-config ✔
Required: eigen ✘, ffmpeg ✘, jpeg ✘, libpng ✘, libtiff ✘, numpy ✘, openexr ✘, python@2 ✘
==> Caveats
opencv@2 is keg-only, which means it was not symlinked into /usr/local,
because this is an alternate version of another formula.
==> Analytics
install: 1,473 (30 days), 5,485 (90 days), 19,637 (365 days)
install_on_request: 1,078 (30 days), 3,943 (90 days), 15,409 (365 days)
build_error: 0 (30 days)
（ペチン！）よし、じゃあぶちこんでやるぜ！
$ brew install opencv@2
できた。
追補
opencv_traincascade使いたいのですが、どうすればよいのでしょうか。。。