These special characters exist only in BSD systems and the GNU system.
The LNEXT character is recognized only when
IEXTENis set, but in both canonical and noncanonical mode. It disables any special significance of the next character the user types. Even if the character would normally perform some editing function or generate a signal, it is read as a plain character. This is the analogue of the C-q command in Emacs. “LNEXT” stands for “literal next.”
The LNEXT character is usually C-v.
The DISCARD character is recognized only when
IEXTENis set, but in both canonical and noncanonical mode. Its effect is to toggle the discard-output flag. When this flag is set, all program output is discarded. Setting the flag also discards all output currently in the output buffer. Typing any other character resets the flag.
The STATUS character's effect is to print out a status message about how the current process is running.
The STATUS character is recognized only in canonical mode, and only if
NOKERNINFOis not set.