Remove duplicate blank lines Sed Template

What this template solves

Use this template to normalize text that contains too many consecutive blank lines while still keeping one visual separator between blocks.

Open the workspace with this template preloaded, then refine it for your own file and text pattern.

Sample input

alpha


beta


gamma

Prompt to start from

Remove duplicate blank lines but keep a single blank line between sections

Expected command

sed '/^$/N;/^\n$/D'

Best for

Clean pasted notes that contain many duplicate blank rows.
Normalize generated docs or reports with excessive spacing.
Prepare text for sharing while preserving section separation.

How to use this template

1Check whether you want to remove every blank line or only collapse repeated blank lines.
2Copy the sed command that removes consecutive duplicate empty rows.
3Preview on representative sample text, then run the platform-specific file-edit command if needed.

Template FAQ

How do I remove duplicate blank lines but keep one separator line?

A common sed approach is `sed '/^$/N;/^\n$/D'`, which collapses consecutive empty rows while preserving a single blank line between blocks of text.

What is the difference between delete-empty-lines and remove-duplicate-blank-lines?

Delete-empty-lines removes every blank row, while remove-duplicate-blank-lines preserves one empty separator and only removes repeated duplicates. That makes it better for keeping readable section spacing.

Related templates

Explore nearby sed workflows that target similar replace, cleanup, filtering, or rewrite tasks.

Delete empty lines

Cleanup

Remove blank and whitespace-only lines.

sed '/^\s*$/d'

Normalize whitespace

Cleanup

Collapse repeated spaces and tabs into one clean separator.

sed 's/[[:space:]]\+/ /g'

Remove trailing spaces

Cleanup

Delete trailing spaces and tabs at the end of each line.

sed 's/[[:space:]]\+$//'