One Quickie

gdb'ing specific architectures (gdb->Debugging)
With a fat binary (32/64bit), gdb picks the 64 bit version. If you're trying to debug a 32-bit unit test on the command-line though, the 64-bitness of /Developer/Tools/otest gets in the way:
% gdb /Developer/Tools/otest
2008-10-31 19:29:50.834 otest[711:813] Error loading
265): no suitable image found.  Did find:
        mach-o, but wrong architecture
2008-10-31 19:29:50.887 otest[711:813] The test bundle at
build/Debug/Tests.octest could not be loaded because it is built for a
different architecture than the currently-running test rig (which is
running as unknown).
2008-10-31 19:29:50.904 otest[714:203] *** NSTask: Task create for
path '/blah/blah/blah/build/Debug/Tests.octest/Contents/MacOS/Tests'
failed: 8, "Exec format error".  Terminating temporary process.
You can supply a -arch flag to pick what you want:
% gdb -arch i386 /Developer/Tools/otest
And then debug your 32-bit unit test.

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