Hi, I first install boost.build and bjam. Then I try to make the building boost library a little bit slower by adding some time to sleep between every two calls to g++. So I add this in /etc/site-config.jam using gcc ; ; "sleep 10; g++" ; However, when calling bjam to install, it gives this error: $ ./bjam install \/etc/site-config.jam:5: syntax error at keyword ; /etc/site-config.jam:5: in load rule sleep 10; g++ unknown in module pch. /tmp/boost_1_40_0/tools/build/v2/kernel/modules.jam:283: in import /tmp/boost_1_40_0/tools/build/v2/tools/gcc.jam:19: in load /tmp/boost_1_40_0/tools/build/v2/kernel/modules.jam:283: in import /tmp/boost_1_40_0/tools/build/v2/build/toolset.jam:37: in toolset.using /tmp/boost_1_40_0/tools/build/v2/build/project.jam:874: in using project-config.jam:12: in modules.load /tmp/boost_1_40_0/tools/build/v2/build-system.jam:241: in load-config /tmp/boost_1_40_0/tools/build/v2/build-system.jam:407: in load-configuration-files /tmp/boost_1_40_0/tools/build/v2/build-system.jam:538: in load /tmp/boost_1_40_0/tools/build/v2/kernel/modules.jam:283: in import /tmp/boost_1_40_0/tools/build/v2/kernel/bootstrap.jam:138: in boost-build /tmp/boost_1_40_0/boost-build.jam:16: in module scope Some advice how to solve this? Thanks and regards!