add install path to /opt/compiler/gcc-4.8.2/bin:/home/liaogang/.jumbo…

…/opt/sun-java6/bin:/home/liaogang/.jumbo/opt/sun-java6/jre/bin:/home/liaogang/.jumbo/opt/sun-java6/db/bin:/home/liaogang/.jumbo/bin/core_perl:/home/liaogang/.jumbo/bin:/usr/local/ganglia/sbin:/usr/local/ganglia/bin:/usr/local/apr/bin:/usr/local/cuda/bin:/opt/compiler/gcc-4.8.2/bin:/home/liaogang/.jumbo/opt/sun-java6/bin:/home/liaogang/.jumbo/opt/sun-java6/jre/bin:/home/liaogang/.jumbo/opt/sun-java6/db/bin:/home/liaogang/.jumbo/bin/core_perl:/home/liaogang/.jumbo/bin:/usr/local/ganglia/sbin:/usr/local/ganglia/bin:/usr/local/apr/bin:/usr/local/cuda/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/bin:/usr/bin:/opt/ibutils/bin:/opt/bin:/home/opt/bin:/usr/local/sbin:/usr/sbin:/sbin:/opt/bin:/home/opt/bin:/home/liaogang/bin

ISSUE=4594417

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1424 1ad973e4-5ce8-4261-8a94-b56d1f490c56

doc/build/build_from_source.md

@@ -126,6 +126,8 @@ cd build
 # you can add build option here, such as:    
 cmake -DWITH_GPU=ON -DWITH_DOC=OFF -DCMAKE_INSTALL_PREFIX=<path to install> ..
 make -j `nproc` && make install
+# PaddlePaddle installation path
+export PATH=<path to install>/bin:$PATH
 ```
 **Note**