Tails

When running ’vm.execute("pgrep -f $something")' it's currently the case that pgrep@ lists its own pid (and hence never fails, which could be of great importance), unlike when you run it natively, and unlike “The running pgrep or pkill process will never report itself as a match.” in pgrep(1).

The practical problem is the (potentially serious) surprise one can be hit by when writing a step definition.

Why is that happening? Are other tools misbehaving?

Having a look in the pgrep sources may help us understand this issue.