Use The 'strace', Luke... We can in fact trace out the way a process behaves (including loading of shared libraries) using the 'strace' command. This command traces all system calls executed by the process, and shows us their parameters and their return values. We activate 'strace' either for a new process ('strace sendmail'), or by attaching it to a given PID ('strace -p '). The output of 'strace' is very verbose, and requires some practicing in order to understand it correctly. An experienced admin/programmer will be able to identify networking problems, disk mounting problems, missing libraries problems and a host of other problems, just by looking at an 'strace' dump.