I noticed that some videos in this course are marked with either (Optional) or a yellow star. Are these not required for taking the test? Just curious as two of the videos marked as optional are compress/uncompress files and backup files which I thought may be on the exam.
Optional means that you shouldn’t get a question on the given topic, but it is good to know for broader knowledge. Having said that, you absolutely should know how to use tar and gzip (and probably zip, unzip too) for compression. Sounds like that lecture should have any optional tag removed.
Yellow star indicates recently added content in response to a curriculum change in the exam.