I've successfully installed Qwt in Xubuntu 12.04(qmake -> make -> make install). But now I need to set the Qwt path to run time linker of Xubuntu. In manual it's given like -

If you have installed a shared library it's path has to be known to the run-time linker of your operating system. On Linux systems read "man ldconfig" ( or google for it ). Another option is to use the LD_LIBRARY_PATH (on some systems LIBPATH is used instead, on MacOSX it is called DYLD_LIBRARY_PATH) environment variable.

But being newbie to Linux environment, I'm not able to proceed further. Please help me with this.