Terminal control/Clear the screen

From Rosetta Code
Task
Terminal control/Clear the screen
You are encouraged to solve this task according to the task description, using any language you may know.

Clear the terminal window.

6502 Assembly[edit]

Works with: [VICE]

This example has been written for the C64 and uses the CHROUT KERNEL routine. Compile with the Turbo Macro Pro cross assembler:

tmpx -i clrscr.s -o bin/clrscr.prg

Run with:

SYS680
; C64 - Terminal control: Clear the screen
 
; *** labels ***
 
chrout = $ffd2
 
; *** main ***
 
*=$02a8  ; sys 680
 
lda clr  ; A = {CLR}
jsr chrout  ; Output a character in A to the current
 ; output device (default: screen).
rts
 
; *** data ***
 
clr .byte $93  ; the CLR control code
 ; see https://en.wikipedia.org/wiki/PETSCII
 
Works with: [6502asm.com] version 1.2
Works with: [6502asm.com] version 1.5 beta

The 6502asm.com emulator has a 32x32 pixel screen. First we fill this screen with random colored pixels, wait for a keypress and then "clear" the screen (fill it with black pixels).

; 6502asm.com - Clear the screen
 
lda #$00  ; store the start address of the screen ($200)
sta $00  ; at $00 and $01 (high byte in $01)
lda #$02
sta $01
 
ldy #$00  ; Y = 0
fillscreen:
lda $fe  ; A = random number from $fe
sta ($00),y  ; put pixel (random color) to the screen
iny  ; Y++
bne fillscreen  ; loop if Y!=0
inc $01  ; increase address high byte
lda $01
cmp #$06  ; A==6? (screen ends at $05ff)
bne fillscreen  ; no -> loop
 
waitforkeypress:
lda $ff  ; $ff is 0 if no key has been pressed
beq waitforkeypress
 
ldx #$00
lda #$00  ; black
clearscreen:
sta $0200,x
sta $0300,x
sta $0400,x
sta $0500,x
inx
bne clearscreen
 

Ada[edit]

For systems with ANSI terminal handling:

with Ada.Text_IO;
procedure CLS is
begin
Ada.Text_IO.Put(ASCII.ESC & "[2J");
end CLS;

ARM Assembly[edit]

Works with: as version Raspberry Pi
 
 
/* ARM assembly Raspberry PI */
/* program clearScreen.s */
 
/* Constantes */
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
 
.equ BUFFERSIZE, 100
 
/* Initialized data */
.data
szMessStartPgm: .asciz "Program start \n"
szMessEndPgm: .asciz "Program normal end.\n"
szClear: .asciz "\33[2J" @ console clear (id language C)
szClear1: .byte 0x1B
.byte 'c' @ other console clear
.byte 0
szCarriageReturn: .asciz "\n"
 
/* UnInitialized data */
.bss
 
/* code section */
.text
.global main
main:
 
ldr r0,iAdrszMessStartPgm @ display start message
bl affichageMess
//ldr r0,iAdrszClear @ clear screen
ldr r0,iAdrszClear1 @ change for other clear screen
bl affichageMess
ldr r0,iAdrszMessEndPgm @ display end message
bl affichageMess
 
100: @ standard end of the program
mov r0, #0 @ return code
mov r7, #EXIT @ request to exit program
svc 0 @ perform system call
iAdrszMessStartPgm: .int szMessStartPgm
iAdrszMessEndPgm: .int szMessEndPgm
iAdrszClear: .int szClear
iAdrszClear1: .int szClear1
iAdrszCarriageReturn: .int szCarriageReturn
 
/******************************************************************/
/* display text with size calculation */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {r0,r1,r2,r7,lr} @ save registers
mov r2,#0 @ counter length */
1: @ loop length calculation
ldrb r1,[r0,r2] @ read octet start position + index
cmp r1,#0 @ if 0 its over
addne r2,r2,#1 @ else add 1 in the length
bne 1b @ and loop
@ so here r2 contains the length of the message
mov r1,r0 @ address message in r1
mov r0,#STDOUT @ code to write to the standard output Linux
mov r7, #WRITE @ code call system "write"
svc #0 @ call system
pop {r0,r1,r2,r7,lr} @ restaur registers
bx lr @ return
 
 

AutoHotkey[edit]

Reference: http://www.autohotkey.com/forum/topic76532.html

RunWait %comspec% /c cls

AWK[edit]

system("clear")

Axe[edit]

ClrHome

BASIC[edit]

Works with: QBasic
Works with: Locomotive Basic
Works with: ZX Spectrum Basic
Works with: BBC BASIC
CLS

Applesoft BASIC[edit]

HOME

BBC BASIC[edit]

      CLS

or

      VDU 12

or

      PRINT CHR$(12);

GW-BASIC[edit]

10 CLS

IS-BASIC[edit]

100 CLEAR SCREEN

PureBasic[edit]

Clears the whole console content using the current background color.

ClearConsole()

Batch File[edit]

CLS

beeswax[edit]

Using the ANSI escape sequence Esc[2J.

_3F..}`[2J`

Befunge[edit]

Assuming a terminal with support for ANSI escape sequences.

"J2["39*,,,,@

Blast[edit]

clear

Bracmat[edit]

sys$cls&

C[edit]

The C version of the Minesweeper game uses curses.

If perhaps clear screen isn't used, call the function cls to do the trick.

void cls(void) {
printf("\33[2J");
}

Here is the cheaty way no one likes, only works on Windows.

#include <stdio.h>
#include <stdlib.h>
 
void main() {
printf ("clearing screen");
getchar();
system("cls");
}

C#[edit]

System.Console.Clear();

Works on all .NET Core platforms. Throws an exception if output has been redirected to a file.

COBOL[edit]

       PROGRAM-ID. blank-terminal.
 
DATA DIVISION.
SCREEN SECTION.
01 blank-screen BLANK SCREEN.
 
PROCEDURE DIVISION.
DISPLAY blank-screen
 
GOBACK
.

Comal[edit]

PAGE

Common Lisp[edit]

 
(format t "~C[2J" #\Esc)
 

or it could be done passing the 'clear' command to the shell

 
(defun sh (cmd)
"A multi-implementation function equivalent for the C function system"
#+clisp (shell cmd)
#+ecl (si:system cmd)
#+sbcl (sb-ext:run-program "/bin/sh" (list "-c" cmd) :input nil :output *standard-output*)
#+clozure (ccl:run-program "/bin/sh" (list "-c" cmd) :input nil :output *standard-output*))
(sh "clear")
 

D[edit]

extern (C) nothrow {
void disp_open();
void disp_move(int, int);
void disp_eeop();
void disp_close();
}
 
void main() {
disp_open();
disp_move(0, 0);
disp_eeop();
disp_close();
}

Dc[edit]

Using external "clear" binary[edit]

Dc's command to execute shell commands can only be the last command of a line. That's no problem with multi line Dc programs but not very helpful in Dc oneliners:

!clear

Luckily there is a loophole:

[ !clear ] x

Using a terminal control sequence[edit]

A common way to clear the screen with a terminal (assuming XTerm here) control sequence could be to home the cursor ("ESC[H", "1B 5B 48") and then clear to the end of the screen ("ESC[J", "1B 5B 4A").

16i 1B5B481B5B4A P

Elena[edit]

ELENA 3.4 :

public program()
{
console.clear()
}

Erlang[edit]

 
clear()->io:format(os:cmd("clear")).
 

Euphoria[edit]

clear_screen()

F#[edit]

open System
 
Console.Clear()

Forth[edit]

page

Fortran[edit]

Fortran 2008:

program clear
character(len=:), allocatable :: clear_command
clear_command = "clear" !"cls" on Windows, "clear" on Linux and alike
call execute_command_line(clear_command)
end program

Intel Fortran on Windows[edit]

Using console functions, one can also clear the screen without using a system command. See also Clearing the Screen on MSDN.

program clear
use kernel32
implicit none
integer(HANDLE) :: hStdout
hStdout = GetStdHandle(STD_OUTPUT_HANDLE)
call clear_console(hStdout)
contains
subroutine clear_console(hConsole)
integer(HANDLE) :: hConsole
type(T_COORD) :: coordScreen = T_COORD(0, 0)
integer(DWORD) :: cCharsWritten
type(T_CONSOLE_SCREEN_BUFFER_INFO) :: csbi
integer(DWORD) :: dwConSize
 
if (GetConsoleScreenBufferInfo(hConsole, csbi) == 0) return
dwConSize = csbi%dwSize%X * csbi%dwSize%Y
 
if (FillConsoleOutputCharacter(hConsole, SCHAR_" ", dwConSize, &
coordScreen, loc(cCharsWritten)) == 0) return
 
if (GetConsoleScreenBufferInfo(hConsole, csbi) == 0) return
 
if (FillConsoleOutputAttribute(hConsole, csbi%wAttributes, &
dwConSize, coordScreen, loc(cCharsWritten)) == 0) return
 
if (SetConsoleCursorPosition(hConsole, coordScreen) == 0) return
end subroutine
end program

GNU Fortran on Windows[edit]

The preceding program can be compiled with GNU Fortran, with the following interface module for Windows API.

module kernel32
use iso_c_binding
implicit none
integer, parameter :: HANDLE = C_INTPTR_T
integer, parameter :: PVOID = C_INTPTR_T
integer, parameter :: LPDWORD = C_INTPTR_T
integer, parameter :: BOOL = C_INT
integer, parameter :: SHORT = C_INT16_T
integer, parameter :: WORD = C_INT16_T
integer, parameter :: DWORD = C_INT32_T
integer, parameter :: SCHAR = C_CHAR
integer(DWORD), parameter :: STD_INPUT_HANDLE = -10
integer(DWORD), parameter :: STD_OUTPUT_HANDLE = -11
integer(DWORD), parameter :: STD_ERROR_HANDLE = -12
 
type, bind(C) :: T_COORD
integer(SHORT) :: X, Y
end type
 
type, bind(C) :: T_SMALL_RECT
integer(SHORT) :: Left
integer(SHORT) :: Top
integer(SHORT) :: Right
integer(SHORT) :: Bottom
end type
 
type, bind(C) :: T_CONSOLE_SCREEN_BUFFER_INFO
type(T_COORD) :: dwSize
type(T_COORD) :: dwCursorPosition
integer(WORD) :: wAttributes
type(T_SMALL_RECT) :: srWindow
type(T_COORD) :: dwMaximumWindowSize
end type
 
interface
function FillConsoleOutputCharacter(hConsoleOutput, cCharacter, &
nLength, dwWriteCoord, lpNumberOfCharsWritten) &
bind(C, name="FillConsoleOutputCharacterA")
import BOOL, C_CHAR, SCHAR, HANDLE, DWORD, T_COORD, LPDWORD
!GCC$ ATTRIBUTES STDCALL :: FillConsoleOutputCharacter
integer(BOOL) :: FillConsoleOutputCharacter
integer(HANDLE), value :: hConsoleOutput
character(kind=SCHAR), value :: cCharacter
integer(DWORD), value :: nLength
type(T_COORD), value :: dwWriteCoord
integer(LPDWORD), value :: lpNumberOfCharsWritten
end function
end interface
 
interface
function FillConsoleOutputAttribute(hConsoleOutput, wAttribute, &
nLength, dwWriteCoord, lpNumberOfAttrsWritten) &
bind(C, name="FillConsoleOutputAttribute")
import BOOL, HANDLE, WORD, DWORD, T_COORD, LPDWORD
!GCC$ ATTRIBUTES STDCALL :: FillConsoleOutputAttribute
integer(BOOL) :: FillConsoleOutputAttribute
integer(HANDLE), value :: hConsoleOutput
integer(WORD), value :: wAttribute
integer(DWORD), value :: nLength
type(T_COORD), value :: dwWriteCoord
integer(LPDWORD), value :: lpNumberOfAttrsWritten
end function
end interface
 
interface
function GetConsoleScreenBufferInfo(hConsoleOutput, &
lpConsoleScreenBufferInfo) &
bind(C, name="GetConsoleScreenBufferInfo")
import BOOL, HANDLE, T_CONSOLE_SCREEN_BUFFER_INFO
!GCC$ ATTRIBUTES STDCALL :: GetConsoleScreenBufferInfo
integer(BOOL) :: GetConsoleScreenBufferInfo
integer(HANDLE), value :: hConsoleOutput
type(T_CONSOLE_SCREEN_BUFFER_INFO) :: lpConsoleScreenBufferInfo
end function
end interface
 
interface
function SetConsoleCursorPosition(hConsoleOutput, dwCursorPosition) &
bind(C, name="SetConsoleCursorPosition")
import BOOL, HANDLE, T_COORD
!GCC$ ATTRIBUTES STDCALL :: SetConsoleCursorPosition
integer(BOOL) :: SetConsoleCursorPosition
integer(HANDLE), value :: hConsoleOutput
type(T_COORD), value :: dwCursorPosition
end function
end interface
 
interface
function GetStdHandle(nStdHandle) bind(C, name="GetStdHandle")
import HANDLE, DWORD
!GCC$ ATTRIBUTES STDCALL :: GetStdHandle
integer(HANDLE) :: GetStdHandle
integer(DWORD), value :: nStdHandle
end function
end interface
end module
 

FreeBASIC[edit]

' FB 1.05.0 Win64
 
' FreeBASIC has a built in Cls command which clears the console on Windows
' but it may still be possible to scroll the console to view its
' previous contents. The following command prevents this.
 
Shell("Cls")
Sleep

Go[edit]

External command[edit]

Probably most reliable way to clear the screen.

package main
 
import (
"os"
"os/exec"
)
 
func main() {
c := exec.Command("clear")
c.Stdout = os.Stdout
c.Run()
}

ANSI escape code[edit]

Simplest, if your terminal supports the ANSI code you want.

package main
 
import "fmt"
 
func main() {
fmt.Print("\033[2J")
}

Ncurses[edit]

More complex, but works across multiple terminal types.

Library: curses
package main
 
import (
"log"
"time"
 
"code.google.com/p/goncurses"
)
 
func main() {
s, err := goncurses.Init()
if err != nil {
log.Fatal("goncurses:", err)
}
defer goncurses.End()
s.Println("Clearing screen...")
s.Refresh()
time.Sleep(1 * time.Second)
 
s.Clear() // clear screen
 
// Goncurses saves the screen on Init and restores it on End. This
// GetChar() allows you to see the effect of the program before it exits.
s.GetChar() // press any key to continue
}

GUISS[edit]

This will only work if the terminal is sitting at a prompt.

Window:Terminal,Type:clear[enter]

Haskell[edit]

 
import System.Console.ANSI
 
main = clearScreen
 

Icon and Unicon[edit]

Example works for both Icon and Unicon. Determine which system command to call by querying &features at run time. Alternately, the related preprocessor symbols can be used to select the operating system.

procedure main ()
if &features == "MS Windows" then system("cls") # Windows
else if &features == "UNIX" then system("clear") # Unix
end

J[edit]

Note: this is specific the java+gdi based J ide.

smwrite_jijs_ ''

Java[edit]

Using the ANSI escape sequence:

public class Clear
{
public static void main (String[] args)
{
System.out.print("\033[2J");
}
}

An alternative sequence:

public class Clear
{
public static void main (String[] args)
{
System.out.print("\033\143");
}
}

jq[edit]

"\u001B[2J"

Example:

$ jq -n '"\u001B[2J"'

Jsish[edit]

Using ANSI terminal control codes.

/* Terminal Control, clear the screen, in Jsish */
function cls() { printf('\u001b[2J'); }
 
;cls();
 
/*
=!EXPECTSTART!=
cls() ==> ^[[2Jundefined
=!EXPECTEND!=
*/
Output:
prompt$ jsish -u terminalControlClear.jsi
[PASS] terminalControlClear.jsi

Julia[edit]

 
println("\33[2J")
 

Kotlin[edit]

Works with: Ubuntu version 14.04
// version 1.1.2
 
fun main(args: Array<String>) {
println("\u001Bc") // Esc + c
}

Lasso[edit]

local(
esc = decode_base64('Gw==')
)
 
stdout(#esc + '[2J')

[edit]

cleartext

There is a separate command to reset the turtle graphics window.

clearscreen
cs  ; abbreviation for clearscreen
clean  ; like cs, but doesn't reset turtle position

Lua[edit]

Unix, Linux[edit]

os.execute( "clear" )

Windows[edit]

os.execute( "cls" )

M2000 Interpreter[edit]

We can clear the screen with Form, Cls, Window statements. Each one perform something on the console form except clear it. Form change the size of letters using the size of window. Window change all. Cls change the background color, or use the same (is optional) and optional can set the line for the split screen (from that line we have scrolling). Also we can use Linespace statement (in twips) to set the line space. Statement Form set linespace automatic to give space between lines to full use of the window.

 
Module Checkit {
Pen 14 ' yellow
\\ using form we set characters by rows
\\ this clear the screen
Form 80, 40
\\ magenta for background, all form for vertical scrolling
Cls 5, 0
Print "wait... half second"
Wait 500
\\ clear using background color
Cls
\\ set the background (using html number for color), and set 4th line as top
\\ for scrolling
Cls #11bb22, 3
Print "This is in 4th line"
Wait 1000
\\ now we center the form, using 12000 twips by 8000twips as border
\\ form inside maybe smaller
\\ font size is 16pt of current font
Font "Courier New"
Window 16, 12000, 8000;
Print "This is first line"
Wait 1000
Font "Arial"
\\ set the console form to screen 0, maximized
Window 16, 0
Cls 5 ' magenta
Back {
Cls 15 ' white border
}
}
checkit
 


Mathematica[edit]

Delegating to clear on terminal enabled OS(Mac Os, Linux)

Run["clear"];

Nanoquery[edit]

cls

Nemerle[edit]

Exactly as C#. Because of possible (probable) ambiguity, this is one time it may be prudent to use:

Console.Clear();

rather than importing the Console class with using System.Console; and calling as:

Clear();

NewLISP[edit]

 
(! "clear")
 

In the newLISP command shell, this syntax is also proper:

 
!clear
 

Nim[edit]

import osproc
discard execCmd "clear"

OCaml[edit]

Using the library ANSITerminal:

#load "unix.cma"
#directory "+ANSITerminal"
#load "ANSITerminal.cma"
open ANSITerminal
 
let () =
erase Screen

Octave[edit]

 system clear;
 system('clear');

Pascal[edit]

clrscr;

Perl[edit]

Assuming some ANSI terminal, easiest way is call your system's clear command:

system('clear')

If it's needed often:

$clear = `clear`; # clear simply prints some escape sequence, cache it
#... later:
print $clear;

We can also obtain the sequence using the Term::Cap module:

use Term::Cap;
 
$terminal = Term::Cap->Tgetent();
$clear = $terminal->Tputs('cl');
print $clear;

Perl 6[edit]

sub clear { print qx[clear] }
clear;

Phix[edit]

clear_screen()

PicoLisp[edit]

(call 'clear)

PowerShell[edit]

Clear-Host

ProDOS[edit]

clearscurrentscreentext

Python[edit]

Works with: Python version 2.6
Works with: Ubuntu version 10.10

To clear the screen on Windows, replace 'clear' with 'cls'

import os
os.system("clear")

Or similar to C example (won't work in Winsows console, since it does not recognize ANSI sequences):

print "\33[2J"

On Windows, using functions from the kernel32 DLL:

from ctypes import *
 
STD_OUTPUT_HANDLE = -11
 
class COORD(Structure):
pass
 
COORD._fields_ = [("X", c_short), ("Y", c_short)]
 
class SMALL_RECT(Structure):
pass
 
SMALL_RECT._fields_ = [("Left", c_short), ("Top", c_short), ("Right", c_short), ("Bottom", c_short)]
 
class CONSOLE_SCREEN_BUFFER_INFO(Structure):
pass
 
CONSOLE_SCREEN_BUFFER_INFO._fields_ = [
("dwSize", COORD),
("dwCursorPosition", COORD),
("wAttributes", c_ushort),
("srWindow", SMALL_RECT),
("dwMaximumWindowSize", COORD)
]
 
def clear_console():
h = windll.kernel32.GetStdHandle(STD_OUTPUT_HANDLE)
 
csbi = CONSOLE_SCREEN_BUFFER_INFO()
windll.kernel32.GetConsoleScreenBufferInfo(h, pointer(csbi))
dwConSize = csbi.dwSize.X * csbi.dwSize.Y
 
scr = COORD(0, 0)
windll.kernel32.FillConsoleOutputCharacterA(h, c_char(b" "), dwConSize, scr, pointer(c_ulong()))
windll.kernel32.FillConsoleOutputAttribute(h, csbi.wAttributes, dwConSize, scr, pointer(c_ulong()))
windll.kernel32.SetConsoleCursorPosition(h, scr)
 
clear_console()

Racket[edit]

 
#lang racket
(require (planet neil/charterm:3:0))
(with-charterm
(void (charterm-clear-screen)))
 

Retro[edit]

clear

REXX[edit]

generic[edit]

The REXX programming language does not include a facility to clear the screen natively.

However, it is possile to execute an external system command to achieve this task.

Below is some generic-type boilerplate (REXX) code which (possibly) determines:

  • which REXX is being used
  • which operating system is being used
  • which (external) program to clear the screen


Also, not germane to this Rosetta Code task, the boilerplate code also possibly determines (among other things):

  • if a particular documentation is to be shown
  • which system pool name is to be used for system environmental variables
  • which version of REXX is being used
  • if the program is being invoked as a function, command, or subroutine


The following code works for:

  • PC/REXX
  • Personal REXX
  • CMS REXX
  • TSO REXX
  • R4 REXX
  • ROO REXX
  • KEXX
  • REXX compiler
  • Regina REXX


The intent of the program's boilerplate code is to be able to be executed under most REXXes under most operating systems without changing the boilerplate REXX code.

/*REXX boilerplate determines how to clear screen (under various REXXes)*/
trace off; parse arg ! /*turn off tracing; get C.L. args*/
if !all(arg()) then exit /*Doc request? Show, then exit.*/
if !cms then address '' /*Is this CMS? Use this address.*/
 
!cls /*clear the (terminal) screen. */ /* ◄═══ this is where "it" happens.*/
 
exit /*stick a fork in it, we're done.*/
/*═════════════════════════════general 1-line subs══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════*/
!all:  !!=!;!=space(!);upper !;call !fid;!nt=right(!var('OS'),2)=='NT';!cls=word('CLS VMFCLEAR CLRSCREEN',1+!cms+!tso*2);if arg(1)\==1 then return 0;if wordpos(!,'? ?SAMPLES ?AUTHOR ?FLOW')==0 then return 0;!call=']$H';call '$H' !fn !;!call=;return 1
!cal: if symbol('!CALL')\=="VAR" then !call=; return !call
!env:  !env='ENVIRONMENT'; if !sys=='MSDOS'|!brexx|!r4|!roo then !env='SYSTEM'; if !os2 then !env='OS2'!env; !ebcdic=1=='f0'x; if !crx then !env='DOS'; return
!fid: parse upper source !sys !fun !fid . 1 . . !fn !ft !fm .; call !sys; if !dos then do; _=lastpos('\',!fn); !fm=left(!fn,_); !fn=substr(!fn,_+1); parse var !fn !fn '.' !ft; end; return word(0 !fn !ft !fm,1+('0'arg(1)))
!rex: parse upper version !ver !vernum !verdate .; !brexx='BY'==!vernum; !kexx='KEXX'==!ver; !pcrexx='REXX/PERSONAL'==!ver|'REXX/PC'==!ver; !r4='REXX-R4'==!ver; !regina='REXX-REGINA'==left(!ver,11); !roo='REXX-ROO'==!ver; call !env; return
!sys:  !cms=!sys=='CMS'; !os2=!sys=='OS2'; !tso=!sys=='TSO'|!sys=='MVS'; !vse=!sys=='VSE'; !dos=pos('DOS',!sys)\==0|pos('WIN',!sys)\==0|!sys=='CMD'; !crx=left(!sys,6)=='DOSCRX'; call !rex; return
!var: call !fid; if !kexx then return space(dosenv(arg(1))); return space(value(arg(1),,!env))

Regina[edit]

The regina interpreter supports the rexxcurses plugin, which provides a facility to clear the screen (not shown here).

Scala[edit]

Library: Scala
object Cls extends App {print("\033[2J")}

Ring[edit]

system('clear')

Ruby[edit]

system 'clear'

Or, without reliance on the command line: (equivalent to `clear`)

puts "\e[H\e[2J"

Rust[edit]

print!("\x1B[2J");

Or using casting:

print!("{}[2J", 27 as char);

Seed7[edit]

The function clear is portable and clears the console window. Clear is based on terminfo respectively the Windows console API. A portable function to clear cannot rely on shell respectively cmd.exe commands, because Windows uses CLS and Unix shells use CLEAR, to clear a screen. ANSI terminal escape sequences are also not 100% portable, since not all terminals accept them.

$ include "seed7_05.s7i";
include "console.s7i";
 
const proc: main is func
local
var text: console is STD_NULL;
begin
console := open(CONSOLE);
clear(console);
# Terminal windows often restore the previous
# content, when a program is terminated. Therefore
# the program waits until Return/Enter is pressed.
readln;
end func;

Sidef[edit]

Using a cached-function:

func clear { print(static x = `clear`) };
clear();

Directly invoking the `clear` command:

Sys.run('clear');

Alternatively, without reliance on the command line:

print "\e[3J\e[H\e[2J";

Smalltalk[edit]

Transcript clear.

SmileBASIC[edit]

SmileBASIC's text screen is mixed in with its graphics screen, background screen, and sprites screen.

Text screen only[edit]

To clear just the text screen:

CLS

All screens[edit]

Clearing all of the screens, and resetting display options can be done with:

ACLS

SPL[edit]

#.clear()

Stata[edit]

The cls command clears the Results window, which is the closest to a terminal in Stata.

Tcl[edit]

This only works on systems with ANSI terminal handling, i.e., Unix platforms.

puts -nonewline "\033\[2J"
flush stdout

UNIX Shell[edit]

The clear command can be used to clear the terminal screen:

Works with: Bourne Shell
clear
 
# Alternative method using tput
tput clear

Visual Basic .NET[edit]

System.Console.Clear()

Works on all .NET Core platforms. Throws an exception if output has been redirected to a file.

XPL0[edit]

code Clear=40;
Clear;

zkl[edit]

System.cmd(System.isWindows and "cls" or "clear");
// or, for ANSI terminals: print("\e[2J")