Hey guys,
by chance I tried to do
lazbuild -B myproject.lpi
and about magically I had
Info: (lazarus) Execute Title="Project: Executing command after"
Info: (lazarus) Working Directory=".....some local path...."
Info: (lazarus) Executable=".....some local bat...."
I therefore conclude that passing the -B option is equivalent to doing the Build in the IDE.
Sorry but from the wiki nor from the inline help it was not very clear to me, but ok I am about 50 so my head isn't so fast anymore, if it has ever been.
Note: I have a project whose code is compiled both under linux and windows. I use separate lpis that point to the same lpr/pas. In this way the linux lpi calls a sh and the windows lpi calls a bat, to make similar operations using different syntaxes, of course.