How do I use a macro to automatically increment a number on each line?

Explanation

By recording a one-step macro that increments a number and moves down a line, you can bulk-apply <C-a> across as many lines as needed with a single count. This is perfect when you have a column of identical values that each need to be bumped by 1 — or combined with a multiplier for larger increments.

How it works

• qa — start recording into register a
• <C-a> — increment the first number on the current line by 1
• j — advance to the next line
• q — stop recording
• {N}@a — replay the macro N times

Vim stops automatically when j has nowhere to go (e.g., end of file), so the macro is self-limiting.

Example

Given:

timeout = 10
retries = 10
max_conn = 10

Place the cursor on the first 10, record qa<C-a>jq, then run 2@a:

timeout = 11
retries = 11
max_conn = 11

Tips

• Swap <C-a> for <C-x> to decrement instead
• Prefix a count before <C-a> to step by more than 1: qa5<C-a>jq increments by 5 each line
• To create a sequential series where each line is one higher than the previous (1, 2, 3…), use g<C-a> on a visual selection — that is a different use case
• <C-a> respects :set nrformats: hex (0xff) and octal values are also incremented correctly