This problem was discovered when PCLI scripts were executed in quiet mode, using "pcli run -q -sSomeScript.pcli ...", which then broke the scripts because the ListRevision commands contained in them no longer provided the required output for the scripts to operate on.
There is a PCLI script called FindLabels.pcli that will find version labels, optionally matching a wildcard, used by versioned files on the specified entities. You can download this script from the ZIP file All PCLI Scripts.zip
The attached PCLI script will use the PCLI IsDifferent command to compare the files in the default workfile location to the revisions associated with the default workspace. This script does not list the differences for each file-revision pair. Instead, one of the following message will be displayed for each comparision: