On workstation clusters, you can often attach a debugger to a running
process.
For example, the debugger dbx often accepts a process id (pid)
which you can get by using the ps command. The form is either
dbx a.out 1234or
dbx -pid 1234 a.outwhere 1234 is the process id. One can also attach the TotalView debugger to a running program (See Section Attaching to a running program below).