+As boost has already
+`sudo ./b2 install link=static cxxflags=-fPIC --with-filesystem --with-test --with-log --with-program_options --with-python`
+
+
+## Build with `scons`
+
+- Run `scons` to build the `src/` and `main`. It will generate a library
+`libtracker.a` and an executable file `main` under current folder.
+
+- Run `scons --all` to build source and `test` file. A executable file `TestMain`,
+which is used to run the unit test, will be generated under `test`
+
+- Run `scons --all -c` to clean.
+
+### Run