<p>This is probably easy but I am getting stuck: when I build a solution in Visual Studio - how do extract the exact cmd line for the current build command in order to be able to do the same build from VisualStudio console? </p>

<p>In the output window I can see the single projects in the solution build commands but not the one for the whole solution.</p>

<p>I am on VS2005.</p>

<p>Any help would be appreciated</p>

You can start msbuild from the command line. msbuild understands .sln (solution) files. You can specify the .sln file and the build configuration (debug, release etc.) from the command line.
http://msdn.microsoft.com/en-us/library/ms164311.aspx
Here is the documentation on what you can do with msbuild. MSBuild.exe is installed with the .net framework, not with visual studio. You can find it in c:\windows\microsoft.net\framework\v3.5 (or v2.0.50727)
I searched a bit and found that you can also do a command line build with visual studio using devenv.exe /build, more info here:
http://msdn.microsoft.com/en-us/library/xee0c8y7(VS.80).aspx