Process monitor gives weird error if ps not installed (linux)

[ben-c8y]

Describe the bug On some machines (especially a docker container), "ps" is not installed. This often shows up as this somewhat misleading exception:

if len(info) <= 1: raise Exception('No matching processes found from ps; perhaps process has terminated')

Expected behavior A better error message saying that "ps" could not be executed OR read the process list from /proc without relying on "ps" beinhg present

Affected version(s)

• PySys version(s): 2.2
• Operating System(s): e,g. RHEL8