GDB, the GNU Project debugger, allows you to see what is going on `inside' another program while it executes -- or what another program was doing at the moment it crashed.
ChangeLog Makefile.in README acinclude.m4 aclocal.m4 config.in configure configure.ac configure.srv gdb_proc_service.h gdbreplay.c gdbserver.1 i387-fp.c i387-fp.h inferiors.c linux-arm-low.c linux-cris-low.c linux-crisv32-low.c linux-i386-low.c linux-ia64-low.c linux-low.c linux-low.h linux-m32r-low.c linux-m68k-low.c linux-mips-low.c linux-ppc-low.c linux-ppc64-low.c linux-s390-low.c linux-sh-low.c linux-x86-64-low.c mem-break.c mem-break.h proc-service.c regcache.c regcache.h remote-utils.c server.c server.h spu-low.c target.c target.h terminal.h thread-db.c utils.c win32-i386-low.c