Remove Lines Containing String

Quickly remove every line that contains a specific substring or simple pattern. Paste your text or CSV, enter the string to match, and the tool will delete matching lines. The operation runs in your browser and there is no fixed server-side limit — remove as much as your browser can handle.

How to use

• Paste the text or file contents (CSV/TSV/logs/email threads, etc.) into the editor.
• Open Remove -> Lines containing and enter the string or phrase you want to remove.
• Choose case sensitivity if the UI offers it (match exact case or ignore case).
• Click Remove. Matching lines will be deleted from the result.
• If you want advanced pattern matching, use the Filter tool (Filter a list) which supports regular expressions.

Pattern behaviour (what this tool supports)

• This tool performs simple substring matching by default. Enter the exact text (or a short phrase) that should appear in lines to remove.
• It is not a regex-based remover. For regex or advanced patterns, use Filter a list (supports regex and complex rules).
• Case sensitivity: clarify with the UI option if available; if not specified, assume default substring match (use exact casing or convert input with Case Converter / Trim beforehand).
• Multiline patterns: this tool matches per-line substrings. For multi-line or cross-line matches use the Pattern Extractor (Pattern Extractor) or the Filter tool.

Examples

• CSV — remove rows containing “error”

  Input:
  id,status,message
  1,ok,All good
  2,error,Failed to process file
  3,ok,Completed
  
  Pattern to remove: error
  
  Output:
  id,status,message
  1,ok,All good
  3,ok,Completed
  

• Log file — remove DEBUG lines

  Input:
  2025-01-01 INFO Starting process
  2025-01-01 DEBUG Verbose detail A
  2025-01-01 ERROR Something failed
  2025-01-01 DEBUG Verbose detail B
  
  Pattern to remove: DEBUG
  
  Output:
  2025-01-01 INFO Starting process
  2025-01-01 ERROR Something failed
  

• Email thread — remove signatures

  Input:
  Hi team,
  Please find the report attached.
  Best regards,
  John Doe
  Sent from my iPhone
  
  Pattern to remove: Sent from my iPhone
  
  Output:
  Hi team,
  Please find the report attached.
  Best regards,
  John Doe
  

• Code review — remove single-line comments

  Input:
  // TODO: refactor this
  let x = 1; // inline note
  // temporary hack
  function test(){}
  
  Pattern to remove: // 
  
  Output:
  let x = 1; // inline note
  function test(){}
  

  Note: this example removes any line that contains "// ". Inline comments remain unless the entire line contains the pattern.

What to expect / limits

• There is no fixed server-side file-size limit — the operation runs in your browser. Extremely large inputs (many MB or very long lists) may slow or freeze the browser; consider extracting in smaller chunks if necessary.
• The tool removes whole lines that contain the specified substring. It does not edit partial lines except by deleting the entire matching line.
• Duplicates and ordering are preserved for non-matching lines. If you need to dedupe after removal, use Remove Duplicates.
• If your CSV uses an unusual separator or contains quoted fields, paste the raw CSV text so the tool can process it as plain lines. For more structured CSV cleanup consider converters in the related tools section below.

Tips & edge cases

• If you want to remove lines that do not contain a string, use Remove -> Lines not containing (the inverse operation).
• For case-insensitive removal, normalize text first with Case Converter or use the tool's case option if provided.
• To remove blank lines after filtering, run Remove Empty Lines.
• For complex pattern rules or regex, use Filter a list or Pattern Extractor and then remove matches based on the extracted output.
• Always preview results or work on a copy if the original formatting must be preserved.

FAQ

Does this tool support regular expressions?

No. This tool uses simple substring matching. For regex support use Filter a list, which supports regular expressions and more advanced filters.

Is matching case-sensitive?

By default this tool matches the entered substring exactly. If you need case-insensitive behavior, either normalize the case with Case Converter before running the removal or use the Filter tool which offers more options.

Will removing lines change my original text formatting?

The tool deletes matching lines from the output. Your original pasted text in the editor remains available until you replace it — consider copying the original first if you need to keep it unchanged.

Is there a maximum input size?

There is no fixed server-side limit. The operation is limited by your browser and device memory. For very large files, work in smaller batches to avoid performance issues.

Can I undo the removal?

If the UI provides an undo or history feature, use it. Otherwise, keep a backup copy of the input before applying removals so you can restore it if needed.

Related tools

Use these tools to prepare input or process results:

• Filter a list - advanced filtering with regex support.
• Pattern Extractor - extract strings with custom regex patterns.
• Remove Empty Lines - delete blank lines after filtering.
• Trim - remove leading/trailing spaces before processing.
• CSV to JSON Converter - convert cleaned CSV data for downstream tools.