How do I define or fix a macro using Vimscript instead of re-recording it?

Explanation

Macros in Vim are just text stored in named registers. You can assign any string directly to a register with :let @{register} = '...', which lets you define complex macros programmatically, pre-load them in your vimrc, or surgically fix a macro without recording the whole thing from scratch.

How it works

• :let @q = 'iHello\<Esc>' — assigns a macro to register q that enters insert mode, types Hello, and presses Escape
• Special keys use \<Key> notation inside single-quoted strings with \ escaping, or you can use double-quoted strings with \<Esc>, \<CR>, etc.
• After setting the register, run the macro normally with @q

Example

You recorded a macro that wraps a word in quotes but forgot to advance to the next word at the end. Instead of re-recording, fix it directly:

" Current (broken) macro in register q:
let @q = 'ciw"<C-r>""'

" Fixed: add 'w' at the end to advance to the next word
:let @q = 'ciw"\<C-r>""w'

Or pre-load a commonly used macro in your vimrc:

" Macro to wrap current line in a markdown code fence
let @c = 'O```\<Esc>jo```\<Esc>'

Tips

• Use echo @q to inspect the current contents of a register before editing it
• getreg('q') and setreg('q', 'commands') are the function equivalents — useful when building macros with :execute
• The uppercase register append shortcut qA is handy for one-off extensions, but :let is better for permanent or complex macros stored in your config