About Number Lines
Number Lines prepends a sequential index to each line. Pick from common numbering styles — `1.`, `1)`, `[1]` — or supply zero-padding for fixed-width counters like `001.`. The counter starts at 1 by default and increments by one per line; the line content is otherwise untouched.
Reach for it whenever the human reading the result needs to refer to lines by position: numbered TODO lists, ordered steps in a runbook, footnote markers in research notes, citation lists, or sequenced test cases. The counter is computed automatically — you do not type any numbers — and stays correct when you insert lines and re-run the tool. For unusual counter formats (Roman numerals, alphabetic counters, or a custom prefix that includes the number) compose it from Add Prefix / Suffix and a hand-written counter elsewhere; for the standard styles this tool is the one-step solution.
Examples
Wash the rice
Boil for 10 minutes
Rest off heat1. Wash the rice
2. Boil for 10 minutes
3. Rest off heatStyle `1.` selected. Switch to `1)`, `[1]`, or zero-padded for the alternate formats.
Frequently asked questions
Can I start from a number other than 1?
Yes — the start index is configurable. Set it to a different starting integer if you are continuing a numbered list from a previous chunk.
What does zero-padding do?
It pads the counter to a fixed width with leading zeros, so the numbers line up vertically: `001.`, `002.`, `010.`, `100.`. Useful when the count exceeds 9 and ragged-width numbers would look messy.
How does this differ from Add Prefix / Suffix?
Add Prefix / Suffix uses the same prefix on every line. Number Lines computes a different prefix for each line, namely the sequence number. Use this when the counter matters; use Add Prefix / Suffix for fixed text.
Are blank lines counted?
Yes by default — every line consumes a number, even if it is empty. Run Remove Blank Lines first if you want only non-empty lines to be numbered.