I love tinkering around with the computer and digging into some of the aspects of running Linux, or the more interesting applications it can host. Take the editor Vim. Not a text editor for the masses (to say the least) but it does have an extremely broad and deep set of features and also a whole swathe of settings for them. I've not done much painting recently and have spent some time sorting out my computing experience. For this, I've learnt quite a few new things and it's made me remember how pleasurable learning stuff is.
So : What I have learnt lately a.k.a. WILL. Maybe I will try and document some of these things, if only for my own reference later.
Vim Lookaround
Viewing some old server backup logs (something else I've been "fixing"), I wanted to jump to the next line not starting with a word ("deleting").
I use the Vim text editor and to find a line that starts with a string, use the "^" regex anchor. Press "/" and :
/\v^deleting<cr>
The "<cr>" means press the return/enter key. So "^deleting" matches the word deleting at the start of a line.
The "/v" means interpret the pattern used as "very magic", so no need to quote brackets etc. See vimdoc for an explanation.
Now for the good stuff (and new to me) : to find a line not starting with "deleting", press "/" and :
/\v^(deleting)@!<cr>
This is similar to before but we wrap the pattern in brackets and end with "@!". The "@!" is a negative lookaround (i.e. "lookbehind") i.e. looks for no matching pattern behind us. The "^" means "at start of line" (behind us).
To help retain a piece of knowledge, it's usually useful to write it down somewhere.