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clinuxoutput-redirect

How to discard the output from a system command?

I recently wrote this code to execute system command in C. I just want to measure time performed by this system command.

However, I don't want the output results to be displayed upon executing this program.

#include <stdio.h>
int main(int argc, char* argv[])
{
    system("ls");
    return 0;
}

How do I discard the output from the system command?

Solution

  • When you call system() from C, a shell is invoked to interpret your command. This means you can use shell redirects:

    system("ls > /dev/null");

    and if you want errors to also be suppressed

    system("ls > /dev/null 2>&1");

    However, due to the overhead of running a shell and the fragility of constructing shell commands, it's better to avoid system() when you can.