What does Double Space Lines do that other Text pages on this site do not?

Joins lines with an extra newline. Unlike Undouble Space Lines this expands. Empty fails. Short version: Insert blank lines between lines.

Does Double Space Lines upload my file or text to Tool-You servers?

No. Double Space Lines runs in this browser tab. Files stay on the device. Limit note: Non-empty text.

Should I use Undouble Space Lines instead of Double Space Lines?

Use Double Space Lines when you need Insert blank lines between lines. Use Undouble Space Lines when you need Collapse double-spaced lines. They share a category (Text) but not the same job.

Double Space Lines

Insert blank lines between lines.

Joins lines with an extra newline. Unlike Undouble Space Lines this expands. Empty fails.

What Double Space Lines does

Joins lines with an extra newline. Unlike Undouble Space Lines this expands. Empty fails.

Double Space Lines sits in the Text group on purpose. It is not Undouble Space Lines (Collapse double-spaced lines.) and not Remove Empty Lines (Drop blank lines or collapse runs to one.). Choose this page when you need Insert blank lines between lines. If you stretch Double Space Lines into a neighbor’s job, the result will look wrong even though the site chrome looks the same.

How to use Double Space Lines

Keep this tab on Double Space Lines (/text/double-space-lines). Pasting into the wrong Text tool (for example Undouble Space Lines) changes the job.
Paste or type the input Double Space Lines expects. Path hint: text · double space lines. Insert blank lines between lines.
Apply the Double Space Lines action only. Remove Empty Lines is a different transform (Drop blank lines or collapse runs to one.). Joins lines with an extra newline. Unlike Undouble Space Lines this expands. Empty fails.
Copy the output of Double Space Lines if you need it elsewhere. Size/complexity still follows: Non-empty text.
If the text job is actually Collapse double-spaced lines., leave Double Space Lines and open Undouble Space Lines.

When not to use Double Space Lines

Skip Double Space Lines when a neighbor tool matches better — start with Undouble Space Lines or Remove Empty Lines — or when the description already warns the job will fail. In the tool’s own words: Joins lines with an extra newline. Unlike Undouble Space Lines this expands. Empty fails.

Questions about Double Space Lines

What does Double Space Lines do that other Text pages on this site do not?: Joins lines with an extra newline. Unlike Undouble Space Lines this expands. Empty fails. Short version: Insert blank lines between lines.
Does Double Space Lines upload my file or text to Tool-You servers?: No. Double Space Lines runs in this browser tab. Files stay on the device. Limit note: Non-empty text.
Should I use Undouble Space Lines instead of Double Space Lines?: Use Double Space Lines when you need Insert blank lines between lines. Use Undouble Space Lines when you need Collapse double-spaced lines. They share a category (Text) but not the same job.
What are the limits of Double Space Lines?: Non-empty text. Also: Joins lines with an extra newline. Unlike Undouble Space Lines this expands. Empty fails.