Question

I added some lines in insert mode and now I would like to run some command only on these edit. How to perform it?

Answer 1

Marks '[ and '] locate the start and end lines of newest inserted or changed text. From this, you can simply run

 :'[,']>

to indent those lines once. See :help '[ for more examples. And for instance, formatting the code will happen with

'[=']

and formating a chunk of text with

'[gq']