How do I search for non-printable or control characters in Vim?

Explanation

Files sometimes contain hidden control characters that cause subtle bugs. Vim can search for non-printable characters using hex escape sequences, letting you find and remove invisible bytes like null characters, carriage returns, or embedded control codes.

How it works

• \x00 — matches a null byte
• \x0d — matches a carriage return (^M)
• [\x00-\x1f] — matches any ASCII control character (0-31)
• \%x — alternative hex match syntax: \%xff

Example

/[\x00-\x1f]

Finds all control characters in the file including:
- \x00 (NULL)
- \x09 (TAB)
- \x0a (LF)
- \x0d (CR)

Tips

• Use :%s/[\x00-\x08\x0b-\x1f]//g to strip all control characters except tab and newline
• Press <C-v> followed by a control key in insert/search mode to type literal control characters
• Use :set list to make non-printable characters visible
• ga on a character shows its hex, decimal, and octal values