Add a Prefix to Text Lines
Prepend a prefix to every line of text. Runs entirely in your browser, so your data never leaves your device.
0 chars · 0 lines
Output
The result appears here as you type.
How to use Add a Prefix to Text Lines
- 1. Paste the lines you want to prefix. Enter one item per line, such as a list of commands, a set of file paths, or plain text you want to quote in a reply.
- 2. Set the Prefix. Type the exact text to add to the start of every line, such as a comment marker for code or a quote symbol for a message reply.
- 3. Turn on Skip empty lines. Enable this option so blank lines stay blank instead of receiving the prefix, keeping paragraph breaks visually clean in the result.
- 4. Copy the prefixed lines. Copy the result into your code file, terminal script, or wherever the line-by-line prefix is needed.
When to use Add a Prefix to Text Lines
Add a Prefix to Text Lines inserts the same text at the start of every line in a block, a fast way to comment out code, quote a message, or number-tag a list without editing line by line. Use Add a Prefix to Text Lines whenever a consistent marker needs to appear at the start of each row.
- Commenting out a block of code. A block of Python code needs to be temporarily disabled and the language doesn't support multi-line comments. Adding a hash symbol prefix to every line comments it all out at once.
- Quoting a message in an email reply. You're replying inline to a long message and want the original text quoted with a leading '>' on every line, matching standard email quoting conventions.
- Turning a list into shell commands. A list of filenames needs to become a series of delete commands. Adding 'rm ' as the prefix to every line turns the plain list into ready-to-run shell commands.
- Formatting a numbered log with a consistent marker. A batch of log lines needs a consistent severity tag like 'INFO: ' added to the front of each one before being merged into a larger log file.
Examples
Quote every line
Input
one two
Output
> one > two
About the Add a Prefix to Text Lines tool
Add a Prefix to Text Lines runs as plain JavaScript in your browser tab, with no server behind it. Prepend a prefix to every line of text. Whatever you put in stays on your device from start to finish.
The tool is part of EditSafely's Text Tools section, 211 single-purpose utilities built around the same idea: open the page, get the result, keep your data to yourself.
You can shape the output with 2 settings, including Prefix and Skip empty lines, and the result refreshes the moment you change one. A worked example further down the page shows exactly what the tool produces for a real input.
That local-first design has practical benefits beyond privacy. The tool keeps working on a flaky connection once the page has loaded, results are instant because nothing round-trips to a server, and it is safe to use with confidential material.
Frequently asked questions
Is Add a Prefix to Text Lines free to use?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
Everything happens locally. Your browser downloads the tool's code once, then does all the processing itself; nothing you enter is transmitted, stored or logged. You can even go offline after the page loads and it will still work.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
No. The tool works in any modern browser on desktop, tablet or phone. There is no account to create, no extension to add and no software to install.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.