Hi Teresa,
As Steve mentioned earlier, you control CICore log levels on a context (java class) level using log4j. Some extraneous information that complicates log analysis for troubleshooting purposes can be exlcluded this way.
However, as you mentioned a desire to get "separate log file only for metadata run" makes me wonder that you may be following some wrong technical way to pursue your original business goal.
If you shared what is your true, original business goal, the community might help you and suggest what is the best practice of achieving this. It may end up into some completely different solution, not relying on CICore logging at all. Controlling logging and log levels is sometimes a tool to get something done, but I can't believe it is the goal by itself.
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Dmitriy Alergant, Tier One Analytics