Is there go up line character? (Opposite of \n)

Question

I would like to overwrite something on a line above in a serial console. Is there a character that allows me to move up?

Define "serial console". Is this some terminal emulation program running on a PC, if so which one? — Mark Ransom, Jul 13 '12 at 16:32
FWIW, the reason there's nothing in standard C++ is that it supports the possibility that the output genuinely is a *serial* console. Like a teletype machine or something. The standard doesn't indulge itself in frivolities like moving the cursor ;-) — Steve Jessop, Jul 13 '12 at 16:35
Right now I'm using windows (that's why I'm using PuTTY). But I am also working on Linux, haven't tested it there though. — Sponge Bob, Jul 13 '12 at 16:43
FYI, the notes here might be helpful for someone interested in control sequence(https://notes.burke.libbey.me/ansi-escape-codes/). But with the advent of `colorama` you might not need to learn that at all. — JP Zhang, Mar 14 '22 at 10:35

Sven Marnach · Accepted Answer · 2019-06-04T07:17:24.597

155

Most terminals understand ANSI escape codes. The relevant codes for this use case:

"\033[F" – move cursor to the beginning of the previous line
"\033[A" – move cursor up one line

Example (Python):

print("\033[FMy text overwriting the previous line.")

edited Jun 04 '19 at 07:17

answered Jul 13 '12 at 16:26

Sven Marnach

574,206
118
941
841

This did not work in PuTTY. But thank you, I am sure I will use this for other projects. – Sponge Bob Jul 13 '12 at 16:37
1

@KeeganMcCarthy: This should actually work in PuTTY, but I accidentally missed a square bracket. Please try again. – Sven Marnach Jul 13 '12 at 16:51
1

I re-read OPs question, you are right, the ANSI approach would be a better approach and sufficient here. – Levon Jul 13 '12 at 17:49
Hm, doesn't work in my Konsole bash terminal. However, printing my Python output line with `end=''` and then issueing `print("\033[A")` works, but only for a single line. – AstroFloyd Mar 10 '20 at 10:23
2

You can use the [colorama](https://pypi.org/project/colorama/) package to make the `\033[A` sequence work on Windows. – jtpereyda Oct 14 '20 at 20:16
1

To make it work on windows using the standard library just run ```os.system("")``` – Enderbyte09 Mar 05 '22 at 00:39

score 11 · Answer 2 · edited Nov 06 '19 at 07:49

11

No, not really easily, for that you'd have to use something like the curses library, especially if you want to have more control over cursor placement and do more things programatically.

Here's a link for the Python docs on Programming with Curses, and this short tutorial/example might be of interest too.

I just found this note in the docs in case you are using Windows:

No one has made a Windows port of the curses module. On a Windows platform, try the Console module written by Fredrik Lundh. The Console module provides cursor-addressable text output, plus full support for mouse and keyboard input, and is available from http://effbot.org/zone/console-index.htm.

I believe for C++ there is the NCurses library, the linked page has a section on moving the cursor if you want to poke around with C++. Also there's the NCurses Programming HowTo.

Long time ago I used the curses library with C quite successfully.

Update:

I missed the part about running this on a terminal/serially, for that the ANSI escape sequence, especially for a simple task like yours, will be easiest and I agree with @SvenMarnach solution for this.

edited Nov 06 '19 at 07:49

StvnW

1,772
13
19

answered Jul 13 '12 at 16:20

Levon

138,105
33
200
191

2

I don't agree with "No, not really easily, for that you'd have to use somethink like the curses library". You can do cursor placement with ANSI escape codes, and they work on both Windows and POSIX, and they are easy. – Sven Marnach Jul 13 '12 at 17:24
@SvenMarnach Hmm, ok, so noted. ANSI's been around for a long time, as as the curses library. I believe the curses lib provides a better programmatic interface (though it's been a while since I've used it) and will let you query various screen parameters .. but are you saying other than that there's no need for the curses library? (not trying to argue, just understand) – Levon Jul 13 '12 at 17:29
The curses library is *much* more versatile, of course. And I would definitely use it for any textual user interface on POSIX operating systems. However, the OP wants to do some trivial task (moving the cursor up one line) on Windows. It seems overkill to use a library for this if you can use ANSI sequences, and in this case, the library does not even exist on Windows. – Sven Marnach Jul 13 '12 at 17:33
@SvenMarnach Ah, ok, I see your point, thanks for clarifying. I thought the 2nd half of my first sentence somewhat qualified my statement, but I can see it's perhaps not explicit enough. I'm sure OP can select the solution that works best for them, it's good to have choices. – Levon Jul 13 '12 at 17:35

score 3 · Answer 3 · answered Aug 26 '17 at 07:45

3

for i in range(10):  
    print("Loading" + "." * i) 

    doSomeTimeConsumingProcessing()

    sys.stdout.write("\033[F") # Cursor up one lin

Try this in Python and replace doSomeTimeConsumingProcessing() with any routine needed, and hope it helps

answered Aug 26 '17 at 07:45

user7380054

31
2

2

If anyone wants to do this then just add the kwarg end='\r' to the print function like this: `print('Loading', end='\r')` – Mattwmaster58 Aug 25 '18 at 17:38

score 2 · Answer 4 · answered Oct 14 '20 at 20:19

Carriage return can be used to go to the beginning of line, and ANSI code ESC A ("\033[A") can bring you up a line. This works on Linux. It can work on Windows by using the colorama package to enable ANSI codes:

import time
import sys
import colorama

colorama.init()

print("Line 1")
time.sleep(1)
print("Line 2")
time.sleep(1)
print("Line 3 (no eol)", end="")
sys.stdout.flush()
time.sleep(1)
print("\rLine 3 the sequel")
time.sleep(1)
print("\033[ALine 3 the second sequel")
time.sleep(1)
print("\033[A\033[A\033[ALine 1 the sequel")
time.sleep(1)
print()  # skip two lines so that lines 2 and 3 don't get overwritten by the next console prompt
print()

Output:

> python3 multiline.py
Line 1 the sequel
Line 2
Line 3 the second sequel
>

Under the hood, colorama presumably enables Console Virtual Terminal Sequences using SetConsoleMode.

`> It can work on Windows by using the colorama package to enable ANSI codes` Or you can just do `os.system("")`. — cd-CreepArghhh, Nov 09 '22 at 00:47

score 1 · Answer 5 · answered Mar 27 '14 at 10:39

I may be wrong but :

#include <windows.h>


void gotoxy ( int column, int line )
{
  COORD coord;
  coord.X = column;
  coord.Y = line;
  SetConsoleCursorPosition(
    GetStdHandle( STD_OUTPUT_HANDLE ),
    coord
    );
}

in windows standard console.

score 0 · Answer 6 · answered Jan 04 '23 at 16:21

A simple way based on @Sven Marnach answer:

print(f'\033[A\rxxx')

\033[A: Move cursor one line up.
\r: Move the cursor to the beginning of the line.
xxx: The string to be printed. {xxx} if it is a variable

If you have some extra characters from the previous line after your string, overwrite them with white space, depending on the length of the previous line. Below I added 10 white spaces.

print(f'\033[A\rxxx{' '* 10}')

Is there go up line character? (Opposite of \n)

6 Answers6

Linked

Related