Please check eZCache documentation page.

--clear-tag=<cache_tag>[,<cache_tag2>...]
Expire all caches related to the specified cache tag.
Multiple tags can be provided as a comma separated list.
When combined with the "--purge" parameter, the script will clear the caches instead of expiring them.

If you try to use it with multiple caches, the script will simply fail.

Steps to Reproduce

• Execute the code bellow and confirm nothing will happen

  php ezpublish/console ezpublish:legacy:script bin/php/ezcache.php --clear-tag=content,image --purge
  

Note

It's important eZCache documentation page to be updated as well explaining the multiple tags will be only work with eZP 5.3.4 and higher