Clearing the screen by printing a character?

I'm using chez-scheme and I can't find a way to clear the screen completely. (If someone knows a better way than printing I'd be interested in that too but it's not my question here)

From what I can find clearing the screen by ^L (control-L) or giving the clear command (in bash at least) is equivalent to outputting ASCII character 12: Form feed. However, printing this does nothing. If I use (display (integer->char 12)) it just prints a newline. Another way to encode this character is \f (analogous to \n for newline), but in Python print("\f") as well as in Scheme (display "\f") is just a newline.

Is my understanding of the meaning of ASCII 12 just wrong, or are implementations lacking?

Is there any way to clear the screen that should work across languages, analogous to \n for a newline?


  • If you want to clear the screen, the "ANSI" sequence in a printf


    clears the entire screen, e.g.,

    printf '\033[2J'

    The command-line clear program uses this, along with moving the cursor to the "home" position, again an "ANSI" sequence:


    The program gets the information from the terminal database. For example, for TERM=vt100, it might see this (using \E as \033):


    (the $<50> indicates padding needed for real VT100s). You might notice that the 2 is absent from this string. That is because the cursor is first moved to the home (upper left) position, and the 2 (entire screen) is not necessary. Eliminating that from the string made VT100s a little faster.

    On the other hand, if you just want to reset the terminal, you can use the VT100-style RIS:


    but that has side-effects, besides not being in ECMA-48. These bug reports were for side-effects of \033c:

    Further reading:

    CSI Ps J  Erase in Display (ED).
                Ps = 0  -> Erase Below (default).
                Ps = 1  -> Erase Above.
                Ps = 2  -> Erase All.
                Ps = 3  -> Erase Saved Lines (xterm).