As w32 has .dll files, linux has .so files. The linux .so files offer the big advantage that you can have several versions of them installed at once, as they reflect their version in their filenames. Symbolic links preserve the major versions so you can be less acurate on the version you need. You can check which libs your program will load from which paths there is the ldd program:

yourcitserver# ldd /usr/sbin/citserver =>  (0xffffe000) => /usr/lib/i686/cmov/ (0xb7f4a000) => /usr/lib/i686/cmov/ (0xb7e09000) => /lib/ (0xb7df1000) => /lib/ (0xb7db1000) => /lib/ (0xb7da8000) => /usr/lib/ (0xb7d5d000) => /usr/lib/ (0xb7d29000) => /usr/lib/ (0xb7cf4000) => /usr/lib/ (0xb7cde000) => /usr/lib/ (0xb7be2000) => /lib/ (0xb7bcf000) => /lib/ (0xb7a87000) => /lib/ (0xb7a83000)
        /lib/ (0xb7fae000) => /usr/lib/ (0xb7a76000) => /lib/ (0xb7a48000) => /usr/lib/ (0xb7a31000) => /usr/lib/ (0xb79c3000) => /usr/lib/ (0xb79b4000) => /usr/lib/ (0xb79af000) => /lib/ (0xb7997000) => /usr/lib/ (0xb7946000)

You can modify the paths and which files get loaded by some environment variables:

Your /etc/ keeps your system configuration for library paths. For performance reason your system creates a catalog which is looked at when you run a program. You can refresh this catalog after installing new libs with