Change working directory to currently opened file

Question

How can I change my working directory to the path of the file that I currently have open?

Example

1. current working directory is $HOME

Answer 1

That's actually a builtin. (here's the help link)

:set autochdir

Stick that in your .vimrc or whatnot (:e $MYVIMRC). As mentioned here, sometimes plugins will have issues with that and you need to use something more complicated like

autocmd BufEnter * lcd %:p:h