Check EMC PowerPath managed devices and paths

Shell script runs the command “powermt”, parses its output, looking for devices and paths.
Checks each device for “active” state and each path for “active” mode and “alive” state.

Return values:
OK (0) – all paths up
WARNING(1) – at least one non-active/non-alive path
CRITICAL(2) – device(s) not alive
UNKNOWN(3) – error in command or input

Output strings:
OK – PowerPath: x devices / y paths
WARNING – devicename/serial:path:mode/state …
CRITICAL – devicename/serial:path:mode/state …