strace can also attach to a process that is already running — that shows what it is stuck on right now.
In ~/import-lab the lab-import service loads orders: the importer program should write imported.txt and exit. Today it has been running for an hour, and there is no file.
Attach to importer
In ~/import-lab, find the importer process, attach strace to it for three seconds — first without sudo, then with sudo — and look at its open files in /proc.
First, predict
importer is running but doing nothing. What will strace show in three seconds?
Now start the exercise, run the command and compare your prediction with the output.