Text from script appears in command window

Recently Matlab has been having an odd glitch: when I call scripts, sections of text from those scripts appear in the command window, often repeated again and again (as when the script is going through a loop). This is harmless in that it doesn't affect the processing of the scripts, but frustrating when I want to have some output visible in the command window and it is filled with thousands of lines of code!

For instance, if I run a sample file, the command window looks like this:

>> samplefile
%This is a sample file
%It doesn't really do anything
a=[6 2 3];
b=[3 4 4];
result=a+b;
disp(result);disp(clock);
9 6 7
2020    1    10    14    47    9.4269

I've checked that diary is off, but other than that am not sure what to check or reset to stop this from happening.

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/matlab/ref/echo.html

echo off

[Colin Raymond]

This seemed to work briefly, but in the same Matlab session the issue reappeared and so I'm set back to square one. 'Echo' and 'diary' are both off, yet script text keeps showing up in the command window.

[Steven Lord]

That suggests some code that you're executing turns echo on again at some point. You could try to use dbstop to stop just before echo executes and edit the code to remove the extraneous echo call (or if the echo is necessary make sure it gets turned off, perhaps by using an onCleanup object to ensure it's turned back off even if the function throws an error.)

Yes, I know echo is a built-in function. From the dbstop documentation: "If file is not a MATLAB code file (for instance, it is a built-in or MDL-file), then MATLAB issues a warning. MATLAB cannot pause in the file, so it pauses before executing the file."

[Stephen23]

A simple way to find where the extraneous echo call is to temporarily shadow it with a function that throws an error.

[Colin Raymond]

Using dbstop (very useful) and a test script to check whether echo is on or off led me to find that the issue can be traced to the ncgeodataset object (in the nctoolbox library). Interestingly, none of these scripts leave echo on, so far as I can tell, and also calling ncgeodataset itself isn't the problem, but rather it happens when a variable is called from a file that was created using ncgeodataset. So

file=ncgeodataset('weatherdata.grib');

results in echo staying off, but

thisvar=file{'2_metre_temperature'};

results in echo on. Following each such statement with

echo off

therefore solves the problem (though not quite explaining it!). Thanks all for the assistance.