So, you’re running a program and it hangs. Normally, this isn’t a big deal. Just kill it. But, say its upgrading your mailing lists and you don’t want to kill it for fear that it will leave them in a convoluted mess.
strace to the rescue. Find the PID of the program and run strace -p pid. That will tell you what the program is doing and from there you can figure out how to solve the problem. In my case, it was a bogus lock file, so I removed the file and all was good.