[tstack]

> - regex101 support for quickly defining custom formats is just awesome. Versioning support is slightly broken however, probably because regex101 changed something, so there's no easy way to update the format once you've initially imported it.

There is a `pull` sub-command and it looks like it still works. Running the following will generate a patch file with the updated regex:

    lnav -m format <format-name> regex std regex101 pull

It creates a patch file since the original file might've been modified.

> - There are lots of different filtering capabilities, but there is no unified treatment of them. For example, `:hide-lines-before` and `:filter-out` are at their core the same type of operation: filtering. I should be able to pull up a list of all filters that are currently active and easily add new ones and toggle or delete existing ones.

Adding the time filters to the "Filters" panel sounds like a reasonable request. I've added https://github.com/tstack/lnav/issues/1275 to track.

> - I would expect to be able to create a new view of the data using SQL `SELECT`. A select statement is fundamentally about filtering out some rows (log lines), which feels like a filter, and selecting some particular columns (log fields) and hiding others. The latter point seems like it could be something that should be handled when https://github.com/tstack/lnav/issues/1274 is resolved.

There is the `:filter-expr` command (https://docs.lnav.org/en/v0.12.2/commands.html#filter-expr-e...), have you tried that?