Add a custom prefix to the beginning of each line.
Prepend custom text to every line in your content. Perfect for adding bullet points, comment markers, line numbers, indentation, quote markers, or any repeated prefix. Useful for code commenting, markdown lists, email quoting, and batch text formatting.
Add a custom prefix to the beginning of each line.
Line 1 Line 2 Line 3
First item Second item
Prefix addition prepends specified text to the beginning of every line: adding '- ' to a list creates markdown bullet points. Each line receives the prefix independently, preserving line structure while adding consistent leading content.
Line detection splits text on newline characters (\n) to identify individual lines. Multi-line input becomes an array of lines, each prefixed, then rejoined to create formatted output with maintained line breaks.
Prefix flexibility supports any string: numbers for line numbering, symbols for lists, code comment markers (// or #), indentation (spaces/tabs), or custom markers. The same prefix applies uniformly across all lines.
Code commenting adds language-specific comment markers to multiple lines. Prefixing with '// ' comments out JavaScript code blocks, '# ' comments Python, '/* ' starts multi-line C comments. Batch commenting saves time over line-by-line editing.
Markdown list creation uses prefixes for formatting. Adding '- ' creates unordered lists, '1. ' starts numbered lists (though numbers should increment). Prefixing transforms plain text into structured markdown content.
Email quoting adds '> ' to quoted messages, following email convention. Reply quotes and forwarded content use this prefix to distinguish quoted text from new writing, improving email readability.
Indentation and alignment uses space/tab prefixes for code or text formatting. Adding ' ' (four spaces) indents code blocks in markdown, aligns text columns, or creates visual hierarchy in plain text documents.
Empty lines receive prefixes too, potentially creating unintended formatting. A blank line with '- ' prefix becomes a markdown bullet point with no content, which may render unexpectedly. Some use cases need to skip empty lines.
Existing indentation or prefixes compound with new additions. Lines already starting with spaces get additional prefix, creating nested indentation. Decide whether to preserve, remove, or append to existing leading content.
Line ending variations (\n vs \r\n) affect line detection. Windows line endings might create inconsistent splitting. Normalize line endings before prefixing for reliable cross-platform results.
Very long prefixes create readability issues. Adding lengthy strings to every line pushes content far to the right, reducing usable horizontal space. Keep prefixes concise for maintainable formatted output.
Choose context-appropriate prefixes: Code comments use '//', '/*', '#', markdown uses '- ', '>', ' '. Match prefix to output format and avoid using markdown syntax in code or vice versa.
Handle empty lines explicitly: Decide whether to prefix blank lines or skip them. Many formatters exclude empty lines from prefixing to avoid creating marker-only lines that serve no purpose.
Test prefix rendering in target environment: Markdown parsers, code editors, and email clients may interpret prefixes differently. Verify formatted output displays correctly in the intended destination.
Combine with line numbering for clarity: Instead of plain '>>', use '1: ', '2: ', '3: ' for numbered prefixes. Incremental numbering adds structure and makes line references easy in formatted output.
