When someone asks you to supply a backtrace (from a ?segmentation fault, for example), here is roughly what you have to do.

Run the faulting program like this:

$ gdb --args PROGRAM [ARGUMENTS]
(gdb) run
[Segmentation fault.]
(gdb) bt

(!) This will only provide useful information if the executable (and additional libraries) contain debugging symbols, or those are available separartely.

If you're one a Debian GNU/Hurd system, you'll have to have the hurd-dbgsym package installed for debugging Hurd stuff, and perhaps libc0.3-dbg as well if it's inside the glibc.