Here's a preliminary port of strace to FreeBSD. Here are some notes about it : - This couldn't have been done without the sources of the truss utility by Sean Eric Fagan, which were of great help. - The tracing mecanism used by FreeBD is a lot like the SVR4 one, so this port shares a lot of code with the SVR4 port, including the akward event loop when tracing multiple processes. - This works for i386 binaries, although support for alpha processor should be quite straight forward, but I do not have an alpha to test it on. - Tracing linux binaries is not supported yet, but should be possible with some work. - There are some issues with following forks, and only a few FreeBSD specific syscalls are decoded right now. - This was tested on FreeBSD 4.0. I believe the tracing interface is present since at least FreeBSD 3.0, so it "should" work on all latest releases. I have no idea for other BSDs, though. Gaël Roualland