To instruct the dynamic loader to check a certain directory first, set the LD_LIBRARY_PATH variable to the directories that you would like searched. Separate multiple paths using commas; for example:

# export LD_LIBRARY_PATH="/usr/lib/old:/opt/lib"

After LD_LIBRARY_PATH has been exported, any executables started from the current shell will use libraries in /usr/lib/old or /opt/lib if possible, falling back to the directories specified in /etc/ld.so.conf if some shared library dependencies are still unsatisfied.

We've completed our coverage of Linux shared libraries. To learn more about shared libraries, type man ldconfig and man ld.so.