There are both command-line (glbsp) and windowed (glBSPX) versions of the program in the package. glBSP can either insert the GL nodes in the map WAD, or create an external .GWA file. The node builder supports GL nodes v1, v2, v3, and v5; but not v4 which is exclusive to DeePBSP. GL nodes v1, v3 and v4 are officially deprecated formats.
The default behavior is to create v2 nodes, or v5 nodes instead if certain limits are reached by the map. It will also create ZDBSP compressed nodes instead of regular nodes in such cases where limits are reached.
Although the GL node specifications support a GL_PVS lump for potentially visible set information, this is considered optional and glBSP will not create such data. Another tool, glVIS, should therefore be used in complement to glBSP if building such information is desired.