Syntax

── ? ── CHAR ─┬───────────────────────────────────────────┬────────────%
              ├─ BACK ────┬─ = ─┬─<special character>─────┤
              ├─ CONTROL ─┤     └─<control char mnemonic>─┘
              ├─ DEL ─────┤
              └─ END ─────┘

Explanation

The ?CHAR command allows four of the characters reserved for special use at a specific terminal to be redefined. The dynamically alterable characters that can be changed during a session and the corresponding Teletype default character for each character follow:

The BACK, CONTROL, DEL, and END options cause redefinition of the terminal backspace, control, line delete, and end-of-text characters, respectively. The ?CHAR command cannot be used to redefine the BACK, DEL, and END characters for a pseudostation. If this is attempted, the following error message is displayed:

?CHAR CANNOT REDEFINE BACK, DEL, AND END FOR PSEUDOSTATION

The current state of these four characters can be interrogated by entering ?CHAR without additional text. Characters are represented in the response by graphics, mnemonic names (if graphic representation is not appropriate), or two-digit hexadecimal notation (if no mnemonic exists). Lowercase letters are represented by the uppercase equivalents preceded by a slash.

These reserved characters revert to the default specifications at log-off and halt/load time.

EXAMPLES

?CHAR
#BACK = NUL, CONTROL = ?, DEL = DEL, END = CR

?CHAR CON=*
#BACK = NUL, CONTROL = *, DEL = DEL, END = CR 

?CHAR BACK=BS
#BACK = BS, CONTROL = *, DEL = DEL, END = CR