How to add or load shared library on linux ?

I have referred following steps :

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1. As root, edit file /etc/ld.so.conf. Add a line like /usr/local/pgsql/lib
2. Then run command /sbin/ldconfig //to configure dynamic linker run-time bindings
3.#In a bash shell, type
export LD_LIBRARY_PATH=/usr/local/pgsql/lib //set path for the bash shell
4#In a csh shell, type
setenv LD_LIBRARY_PATH /usr/local/pgsql/lib
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