Illegal character

In computer science, an illegal character is a character that is not allowed by a certain programming language, protocol, or program.^[1] To avoid illegal characters, some languages may use an escape character which is a backslash followed by another character.^[2]

Examples

Windows

In the Windows operating system, illegal characters in file and folder names include colons, brackets, question marks,^[3] and null characters.^[4]

Illegal characters in Windows file names^[4]

Character	Name
<	less than
>	greater than
:	colon
"	speech marks
/	forward slash
\	backslash
|	pipe
?	question mark
*	asterisk