By default, the dynamic loader (/lib/ld-linux.so.2) searches through /lib and /usr/lib for dynamic libraries that are needed by programs when you run them. However, if there are libraries in directories other than /lib and /usr/lib, you need to add them to the /etc/ld.so.conf file in order for the dynamic loader to find them. Two directories that are commonly known to contain additional libraries are /usr/local/lib and /opt/lib, so we add those directories to the dynamic loader's search path. Create a new file /etc/ld.so.conf by running the following: cat > /etc/ld.so.conf << "EOF" # Begin /etc/ld.so.conf /usr/local/lib /opt/lib # End /etc/ld.so.conf EOF Although it's not necessary to add the /lib and /usr/lib directories it doesn't hurt. This way it can be seen right away what's being searched and a you don't have to remember the default search paths if you don't want to.