Suricata

From https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Unit_Tests I know how to enable debug and print debug info. It says ' SC_LOG_OP_FILTER="(something|somethingelse)" suricata u ' . My question is how can I know what 'something' and 'somethingelse' can be.
I need to print this log info in ‘src/detect.c’ Line 758 SCLogDebug("inspecting signature id %"PRIu32"", s>id); So how to setup my environment variable SC_LOG_OP_FILTER and why it works(how can i find it). Thanks!