I agree with the ‘Vim is not an IDE’ paradigm. But there are times when there isn’t an IDE. Here’s what I use in those situations:
Disclaimer: The ubiquity of Language Server Protocol servers, linters and fixers since I wrote this have also brought some great refactoring capabilities to Vim (and other editors). IMO they are a long way from equaling the capabilities of a purpose-built IDE (I prefer ALE and nvim-lspconfig for these kinds of features). See other answers on this question for more info!
:grep, :vimgrep, :GrepperAg, :Ggrep
Refactoring that has more to do with regular replacements I usually use :grep on my project tree and then record a macro to do the refactor – :g and :s are no brainers. Usually it’ll let me quickly modify a large number of files with very little effort. Honestly, I use this method more than any other.
Depending on your workflow the built-in commands might be slow/inconvenient. If you use git, then you’ll wanna use the excellent Fugitive plugin and its :Ggrep command to only search files checked into git. I also like the vim-grepper because it is search-tool-agnostic (supports ag, sift, ripgrep, etc) and speedy.
:argdo, :cdo, and :bufdo
:cdo and :argdo are handy to execute vim commands over a set of files.
command line
When it’s harder to determine the list of files that need changes via :vimgrep I resort to the command line grep/find commands to more closely curate the list of files that I need to refactor. Save the list to a text file and use :e and a mashup of macro recordings to make the changes I need to make.
I find that the less rusty I keep my macro recording skills the more useful I find Vim for refactoring: feeling comfortable saving/restoring from registers, incrementing/decrementing register counter variables, cleaning/saving macro recordings to file for later use, etc.
Update
Since writing this more videocasts for the methods I describe have been published on vimcasts.org (I encourage you to watch ALL the Vimcasts!). For refactoring watch these ones:
- Substitution with :Subvert
- Project wide search/replace
- Search multiple files with :vimgrep
- Use :argdo to change multiple files
Vimgolf is also a great way to practice.