Pass commands to executable run through system command

I have an executable provided by an external organization that I have opened with the system command, but I need to then automatically pass it inputs and my attempts to far have failed. The executable takes 4 inputs - the first and last are numeric, the middle two are text. I have tried packaging the inputs into a text file to no avail. Here is what it looks like (I've tried a bunch of things so this is not as clean as it started):

In1                =   '1';
In2                =   'C:\Dir1\File1.dat';
In3                =   '02/09/2026 16:00';                                
In4                =   '0.5';
fileID             =   fopen('parameters.txt','w');
fprintf(fileID,'%s\r\n %s\r\n %s\r\n %s', In1,In2,In3,In4);
fclose(fileID);
system('C:\Dir2\main.exe < parameters.txt');

The function opens in the MATLAB command window but then just waits for me to manually input each input, and the whole reason I am doing this is to be able to run this multiple times for a bunch of variations, collect the data, and then process it and display it.

[Steven Lord]

Have you checked with the external organization that provided you the executable, to confirm that the executable is designed/intended to be run in a non-interactive environment rather than requiring interactivity? Does it require certain input arguments (like the -batch startup option for MATLAB) to bypass prompting for input from the user?

Answer 1

[Matt J]

Perhaps as follows?

In1 = '1';
In2 = 'C:/Dir1/File1.dat';
In3 = '02/09/2026 16:00';
In4 = '0.5';

cmd = sprintf('C:/Dir2/main.exe %s "%s" "%s" %s', ...
              In1, In2, In3, In4);

system(cmd);

[Matt J]

Or,

In1 = 1;
In2 = 'C:/Dir1/File1.dat';
In3 = '02/09/2026 16:00';
In4 = 0.5;

cmd = sprintf('C:/Dir2/main.exe %d "%s" "%s" %.3g', ...
              In1, In2, In3, In4);

system(cmd);

[Stephen Hall]

No joy. It runs the executable but then just waits for manual input instead of accepting the preloaded inputs.

[Matt J]

Are you sure the executable takes the syntax you have described to us? What happens if you manually call the executable with the same 4 arguments outside of Matlab, from a Windows command prompt:

C:/Dir2/main.exe 1 "C:/Dir1/File1.dat" "02/09/2026 16:00" 0.5'

Answer 2

[Walter Roberson]

You could use the .NET facilities, System.Diagnostics.Process . See the Question at https://www.mathworks.com/matlabcentral/answers/414795-run-exe-with-an-input-file-and-close-upon-process-exit for an outline of the code of passing in standard input.

[Walter Roberson]

Your executable appears to be bypassing standard input methods. Possibly .NET stdinput methods will work, perhaps not. If not, then there is not much you can do about the situation.