What are VIM macros and how do you use them?

A macro records a sequence of keystrokes (q + a letter to start, q to stop) so you can replay it with @letter on many lines.

Macros are vim's answer to "do this same edit 50 times." You record once into a named register, then @a replays it; 10@a runs it ten times. The trick to a reusable macro is making each repetition self-positioning — end the recording by moving to the next line (e.g. j), so replaying naturally marches down the file.

Recording a macro:

1. q + letter (e.g., qa) - Start recording to register 'a'
2. Perform your actions
3. q - Stop recording

Playing a macro:

• @a - Play macro from register 'a'
• 5@a - Play macro 5 times
• @@ - Repeat last macro

Example workflow:

qa          " Start recording to 'a'
I           " Insert at line start
# TODO:     " Type the prefix
Esc         " Back to Normal
j           " Move to next line
q           " Stop recording

10@a        " Apply to next 10 lines

Tip: Macros are powerful for bulk editing tasks like reformatting data or adding boilerplate to multiple lines.