Suppressing command output

I am using the function "system(<SOME COMMAND>)" in a function. The command I'm calling has a lot of screen outputs that I'd like to suppress. How can I do that?

Answer 1

[Fangjun Jiang]

try below. It just saves the screen outputs.

system('dir >output.txt')

[John F]

Works. It's been so long since I've had to remember the old DOS commands. Thanks!

[Jason Ross]

Or if you honestly don't care about the screen output,

system('dir 1>NUL 2>NUL')

Will just send it off to the bit-bucket.

[Fangjun Jiang]

Thanks, Jason! Nice to know. Is this 1 and 2 refer to MATLAB fid 1 and 2?

[Jason Ross]

I've always thought of it as stdout (1) and stderr (2). I've used this extensively outside of MATLAB for other scripting duties. There's a nice summary of redirection commmands at

http://www.robvanderwoude.com/redirection.php

Answer 2

[Helder Magalhães]

It's also possible to use "system" (console) based filtering to avoid the whole output to be redirected to Matlab. For example, taking a directory listing in Windows environment:

% the first part only lists text files, including details
% the part after the pipe filters relevant lines
% (to only dump filenames, use 'dir /b' instead)
sys_cmd = 'dir "C:\MyDirectory\*.txt" | find ".txt"';
system(sys_cmd, '-echo');

I wouldn't generally recommend using system calls often, as it may easily break the possibility of porting your software/environment to another platform. But for quick experiments/diagnostics it can become very handy, specially if one is familiar with command-line environment.