U+0000..U+0008, U+000B..U+000C, U+000E..U+001F, U+007F..U+009F
CONTROL CHARACTER

Non-printing control character that does not belong in text.

Codepoint

U+0000..U+0008, U+000B..U+000C, U+000E..U+001F, U+007F..U+009F

Short

CTRL

Group

control-char

Class

invisible

Default

removed

Replaced by

removed, no substitute

Codepoints

62

What it is

The non-printing control codes inherited from teleprinters and terminals: bell, form feed, escape, delete and their relatives, plus a second block that arrived with the 8-bit character sets.

Tab, line feed and carriage return are excluded. Those do belong in text, and TraceFree PRO never reports them.

Where it comes from

From binary data read as if it were text, from a failed encoding conversion, from terminal output pasted into a document, and from files assembled by a program that never expected a human to read them.

When it belongs

In a document, essentially never. Their presence usually means something upstream treated a file as the wrong kind of thing.

What TraceFree PRO does with it

Context guards can only ever make a cleanup gentler, never sharper. A rule saying “always remove” does not override them.

How to remove it

In TraceFree PRO, turn on the clipboard watcher and copy the text. On the command line:

tracefree clean --backup document.txt
pbpaste | tracefree clean | pbcopy

Report without changing anything — exit code 1 on findings, so it works in CI:

tracefree check -r ./docs

How to write it

This page never prints the character itself, only ways of writing it. A page about invisible characters that contained invisible characters would be unreviewable — and that is the problem the program exists to solve.

Try it on your own text

Paste anything into the browser demo and see what is in it. Same engine as the app, running entirely on your device — nothing is uploaded.

Try it