Thanks for the response!
I really wouldn’t want to write custom PHP scripts… First, I would need to learn PHP and a bit of how the whole TTRSS system works (database etc). Second, I might not have such permissions in the first place. I’m just a user in TTRSS, I don’t have any CLI access to the server, I only have access to the TTRSS web site. Third, writing such scripts is really error-prone and might corrupt the whole database (so I would need to learn to backup the whole database too). Fourth, the solution would not help anyone else or at least wouldn’t be easily usable for them.
FWIW, Thunderbird is one example that has the possibility to run filters manually.
Once I have defined new filters, I think it’s a quite common usecase that one wants to run the filter for the already fetched articles in the database. For instance, adding labels to articles or marking some of them read. I don’t see any problems in this feature as such, just of course some work would be needed to implement it. Do you see any problems or reasons not to include this kind of feature?
Anyway, the filter tool is amazing, because one can create really powerful filters by combining regex rules. I tried it and fell in love immediately.