Remove Empty Lines

About Remove Empty Lines Tool

Remove Empty Lines is a single-purpose text cleaner that scans your input line by line and drops every line that contains no visible characters. The definition used is strict and matches what most developers expect: a line is empty if, after the JavaScript String.prototype.trim() pass, it has length zero — meaning lines containing only spaces, tabs (\t), non-breaking spaces (\u00A0), or any other Unicode whitespace are also removed. The tool preserves the original order of the remaining lines and the exact content within each line including leading and trailing spaces inside that line (only fully-blank lines are dropped). Three optional post-processing steps are available: alphabetical sort (A-Z ascending), reverse sort (Z-A descending, useful for version numbers or dates), and case conversion (UPPER, lower, or unchanged). Common workflows: cleaning code copied from PDFs or Stack Overflow that accumulate double newlines, condensing log files for grep'ing, removing the extra empty rows that Excel CSV export sometimes injects, and tidying email signatures or markdown drafts before publishing.

What counts as an 'empty line' — only truly blank rows or also whitespace-only?

Both. The tool applies String.trim() to each line before checking length, so a line containing only spaces, tabs, multiple non-breaking spaces (the common Word/Google Docs paste artifact U+00A0), zero-width spaces (U+200B), or any combination of Unicode whitespace is removed alongside truly blank '\n\n' rows. If you need to keep whitespace-only lines (e.g. preserving indentation in a code block), copy into a plain text editor first and remove only the literal '\n\n' yourself.

Why is this better than a regex find-and-replace of \n\n+?

Three reasons. First, regex collapse of \n\n+ to \n leaves one blank line per cluster — this tool removes them entirely. Second, regex misses whitespace-only lines unless you write a more complex pattern like /^\s*$\n/gm which not every user knows. Third, this tool offers sort and case-conversion in one pass, so you do not have to chain multiple operations. The performance is equivalent (O(n) line scan) so there is no speed penalty for the convenience.

Does it preserve indentation, tabs, and trailing spaces inside non-empty lines?

Yes. Only lines that are entirely empty or whitespace-only get removed. A line like ' return value' keeps its four leading spaces; a line like 'hello \t' keeps its trailing space and tab. Indentation matters in Python, YAML, and Makefiles, so this preservation is deliberate. If you also want to strip trailing whitespace from kept lines, run the output through a Text Cleaner tool afterwards.

What does the 'Sort results' option actually sort by?

Default sort is locale-aware alphabetical via String.prototype.localeCompare() so accented characters (á, é, ñ, ç) sort in their natural alphabet position rather than after Z. Numbers sort lexicographically (so '10' comes before '2') unless you have numeric strings — for natural number sort use the dedicated Sort Lines tool which has a 'Natural' mode. Reverse sort just calls Array.reverse() after the sort.

Is there a maximum input size and is large file handling supported?

No hard limit. The tool handles 1 million+ lines comfortably because the implementation is a single Array.filter() with String.trim() — O(n) time and O(n) memory. Browser tabs typically allow textarea content up to ~50 MB before paste performance degrades. For multi-gigabyte log files use Unix tools instead: `grep -v '^[[:space:]]*$' file.log` strips empty and whitespace-only lines and runs as a stream without loading the whole file in memory.

Will it remove duplicate blank lines but keep one separator between paragraphs?

No — this tool is aggressive and removes every empty line. If you want to collapse multiple blanks into a single one (preserving paragraph separation in markdown or prose), use the Word Replacer tool with regex enabled: find /\n\s*\n\s*\n+/g and replace with '\n\n'. That keeps prose readable while still cleaning excessive whitespace.

Does the tool send my text anywhere?

No. The filter runs in browser JavaScript on the textarea value, no fetch() to a backend, no analytics with payload. Open the DevTools Network tab and click Remove — you will see zero outbound requests. This makes the tool safe for cleaning confidential data like API keys, employee lists, customer data, or proprietary code snippets without compliance risk.