How can I run a list of commands using the 'system' function

Hi all,

I am using the 'system' command to run an external code that requires inputs after the initial system call:

function [stat,cdmout] = meshgen(filename)

cd Run_cases
cd (filename)
[stat,cmdout]=system('./../../../BINARIESLINUX/UOBSMBV2_4_8.x','-echo')
system('g')
system('g')
cd ../..
end

The problem is that the two 'g' calls are not executed and Matlab requires me to input them manually. How can I get Matlab to input them automatically? (The code will run several hundreds of times so getting this right is very useful)

Thanks

[Mario Malic]

Are you trying to interact with program that is opened by UOBSMBV2_4_8.x?

Answer 1

[Walter Roberson]

You cannot do that in any easy way. However you can create a file containing the input and do I/O redirection.

tfile = tempname();
fid = fopen(tfile, 'w');
fprintf(fid, 'g\ng\n');
fclose(fid);
cleanMe = onCleanup(@() delete(tfile));
cmd = sprintf('./../../../BINARIESLINUX/UOBSMBV2_4_8.x < "%s"', tfile);
[stat, cmdout] = system(cmd, '-echo');

Note that this approach is not interactive -- you cannot use this to read responses from the program and decide what to send it.

There is also a popen() in the File Exchange, which is unidirectional I/O.

To go beyond that you need to use approaches such as opening a named pipe. Or perhaps there is a Java approach.