Updating Shared Library Path

After someone compile and then install a shared library for an application on linux system, the most common problem is the shared library don't load properly. For example, usually you will get an error message like this :

error while loading shared libraries: libqt-mt-so.3: cannot open shared object file: No such file or directory

It means the LD_LIBRARY_PATH is not updated yet, because you install the library manually from the tarball/source using ./configure, make and make install. You can solve this problem by running ldconfig as root. Remember to always run this command after manually installing a new shared library on your linux system.