Imagine you just installed a package into $PREFIX via:

$ ./configure --prefix=$PREFIX
$ make install

To now execute the recently installed piece of software it would be cool to have a generic environment setup script:

$ source generic-setenv.sh $PREFIX

And here it is generic-setenv.sh - to be put in your $PATH:

export PREFIX=$1
export PATH=$PREFIX/bin:$PATH
export LD_LIBRARY_PATH=$PREFIX/lib:$LD_LIBRARY_PATH
export LD_LIBRARY_PATH=$PREFIX/lib64:$LD_LIBRARY_PATH
export PKG_CONFIG_PATH=$PREFIX/lib/pkgconfig:$PKG_CONFIG_PATH
export PKG_CONFIG_PATH=$PREFIX/lib64/pkgconfig:$PKG_CONFIG_PATH