Runtime Linking And Shared Libraries A shared library is a collection of functions and data variables stored in a file, that is loaded by a process during runtime, and is then linked to the rest of the symbols found in the process's address space. A shared library's name ends with the '.so' suffix, by convention. It may have an additional suffix containing a version numbers. Shared libraries are often loaded automatically, while the process starts, by the 'ld.so' linker-loader. The loader searches for the libraries in directories specified by the '/etc/ld.so.cache' file, plus in a few others. This file may be updated using the 'ldconfig' command.