Deleting the last displayed line (or part of it) in the command window.

I'm trying to use the same line in the command window of Matlab to print the progress of my code.

I have read several solutions and currently I'm using the following command:

    disp([repmat(char(8), 1, num_of_Char_to_del)])

This works fine on my Matlab (9.1.0.441655 (R2016b)) when running on Windows 7.

For example when I have the following code

disp('Hello World')
pause
disp([repmat(char(8), 1, 6)])

in an m file with the name 'test.m', and I run the file, first I get

>> test
Hello World

then pressing any key I get

>> test
Hello 
>>

Which is what I want.

However, trying the same exact thing on a Matlab (8.5.0.197613 (R2015a) ) running on Linux server, first I get

    >> test
    Hello World

and if I press any key I get

      >> test
      Hello World

      >>

which is not what I expect.

Can anyone explain what is the issue?

[David J. Mack]

My first guess would be EOL encoding (\r\n vs. \n). Did you try using fprintf instead of disp (which implicitly adds an EOL). So, e.g.

fprintf('Hello World\n');
pause
fprintf(repmat('\b', 1, 6)); %Deletes 'world' and '\n

Greetings, David

[Mohamed Abdalmoaty]

Thanks for your comment. Yes, I have tried fprintf but I could not make it work.

I tried to run your code (on the version running on linux server) and it is not doing what we expect. First I get

>> test
Hello World

but when I press any key I get

>> test
Hello World
>>

Answer 1

[Piotr]

Hello,

here is simple sollution, small upgrade of Jan's answer, without checking the length of the line that you want to clear:

lineLength = fprintf('It is %2.1f degrees outside',21.1);
pause(2)
fprintf(repmat('\b',1,lineLength))

Cheers,

Piotr

Answer 2

[Jan]

Try it without the line break:

fprintf('Hello World');
pause
fprintf(repmat('\b', 1, 6));

How did you open Matlab on the server? Through a text terminal or with the GUI?

[Mohamed Abdalmoaty]

I use PuTTY to connect to the server. This is what happens with the following two commands:

>> fprintf('Hello\b')
Hell>> fprintf('Hello\b\n')
Hello

[Jan]

Di you try to setup the terminal in PuTTY? Look at the "Terminal" tab in the configuration, perhaps the "Keyboard" value "The Backspace Key"? Disable the AutoWrap etc. Make a screen shot from the initial settings at first...

[Mohamed Abdalmoaty]

There are only two options for "The Backspace Key". Changing this option does not change anything in the result of the code. I also disabled the AutoWrap which is on by default, however again with no effect. (I'm attaching my original settings).

[sambhav jain]

hello

i have been running matlab online . In my case it simply prints in next line . the backspace one is not working

Answer 3

[Amin Kassab-Bachi]

If you're trying this from within the command line

msg=fprintf("Anything I want to write\n");
pause
fprintf(repmat('\b', 1, (msg+39))); % covers the length of the message + length of the backspace command.

Otherwise, the answers above should work.