This is probably a request for a plugin.
I'd like to be able to run a filter that provides only matching lines a la grep. I'd like it to filter out of the view any lines that do not match a provided regex.
UberSelection does something similar to that. Inspired in Vim's ex mode. But it will only select the lines for you.
Try this plugin for ST2 and ST3: https://github.com/davidpeckham/FilterLines. I submitted it for Will Bond's Package Control, but it may not be listed yet.
FilterLines is really nice. Would it be possible to add a negate function. Just a small checkbox to switch to the mode to filter the lines that contain not the string or regex.
Cant find in ST2, also not as plugin. Is this an ST3 Feature?
UPDATE: Yes it is, just found it.