How to check if opencv is properly installed in linux/mac

Replace 2.0 with whatever version you have installed. This is correct till 2.1.

In mac, if you have installed using macport then it should be opencv2.1 and it typically install them in /opt/local/lib.

In /usr/local/lib you should have the following libraries

libcvaux.so -> libcvaux.so.2.0
libcvaux.so.2.0 -> libcvaux.so.2.0.0
libcvaux.so.2.0.0
libcv.so -> libcv.so.2.0
libcv.so.2.0 -> libcv.so.2.0.0
libcv.so.2.0.0
libcxcore.so -> libcxcore.so.2.0
libcxcore.so.2.0 -> libcxcore.so.2.0.0
libcxcore.so.2.0.0
libhighgui.so -> libhighgui.so.2.0
libhighgui.so.2.0 -> libhighgui.so.2.0.0
libhighgui.so.2.0.0
libml.so -> libml.so.2.0
libml.so.2.0 -> libml.so.2.0.0
libml.so.2.0.0

And in /usr/local/include/opencv you should have the following header files.

cvaux.h, cvcompat.h, cv.hpp, cvver.h, cvwimage.h, cxcore.hpp, cxflann.h,
cxmisc.h, cxtypes.h, highgui.hpp, cvaux.hpp, cv.h, cvtypes.h, cvvidsurv.hpp,
cxcore.h, cxerror.h, cxmat.hpp, cxoperations.hpp, highgui.h, ml.h

Uninstalling OpenCV older version needs uninstalling the packages and then manually removing the above before making a clean installation.