I have first executed the command: export LD_LIBRARY_PATH=/usr/local/lib
Then I have opened .bash_profile
file: vi ~/.bash_profile
Add
LD_LIBRARY_PATH="/path/you/want1:/path/you/want/2"
to /etc/environment
See the Ubuntu Documentation.
CORRECTION: I should take my own advice and actually read the documentation. It says that this does not apply to LD_LIBRARY_PATH: Since Ubuntu 9.04 Jaunty Jackalope, LD_LIBRARY_PATH cannot be set in $HOME/.profile, /etc/profile, nor /etc/environment files. You must use /etc/ld.so.conf.d/.conf configuration files.* So user1824407's answer is spot on.