Substitution sign
The substitution character (from substitut , SUB for short ) is a control character of the ASCII character set (hexadecimal 1A, decimal 26, screen display ^ Z, keyboard input Ctrl-Z).
use
It stands for any character that should be replaced by another. It is also used for escape sequences . In the CP / M operating system it is used for the end of the file.
Historically, Microsoft DOS actually added the SUB substitution character to the end of a text file as an End of File marker.