How do I increment or add to all numbers in a file using Vim substitution?

Explanation

Vim's expression replacement (\=) in substitutions lets you perform arithmetic on matched text. Combined with submatch(0), you can increment, decrement, multiply, or apply any mathematical transformation to every number in your file.

How it works

• \d\+ — matches one or more digits
• \= — evaluates the replacement as a Vimscript expression
• submatch(0) — returns the matched text as a string
• submatch(0)+1 — Vim auto-converts the string to a number and adds 1

Example

:%s/\d\+/\=submatch(0)+1/g

Before: port 8080 and port 3000
After:  port 8081 and port 3001

Multiply all numbers by 2:

:%s/\d\+/\=submatch(0)*2/g

Tips

• Use with a range: :10,20s/\d\+/\=submatch(0)+100/g
• For simple single-number increment/decrement, use <C-a> and <C-x> in normal mode
• Zero-pad results with printf: \=printf('%03d', submatch(0)+1)
• Combine with :g to only increment numbers on specific lines