How to use stderr with execve

Asked Jul 13 '22 at 07:53

Active Jul 13 '22 at 08:13

Viewed 46 times

I want to see only football in the stdout. And if instead of using echo I use a nonexistant command, then Id like it to be redirected to stderr. Im doubting if its doable.

int main(int argc, char *argv[]) {
        char *tab[] = {"echo", "football", "2> /dev/null", NULL};

        char test [strlen("echo") + strlen( "/bin/" ) +1];
        strcpy(test, "/bin/");
        strcat(test, "echo");
        execve(test, tab, NULL);
    
        return 0;
}

I get football 2> /dev/null but I want only to see football.

edited Jul 13 '22 at 08:13

user3386109

34,287
7
49
68

asked Jul 13 '22 at 07:53

LIsa

5

Unrelated to your problem, by why not `char test[] = "/bin/echo"`? – Some programmer dude Jul 13 '22 at 07:56
7

As for your problem, redirection is handled by the *shell*, not by the commands themselves. If you want redirection, you need to invoke a shell (e.g. `/bin/sh -c "echo football 2> /dev/null"`). – Some programmer dude Jul 13 '22 at 07:57
1

Alternatively to shell usage you can redirect the standard stream(s) yourself. Use these terms in your favorite web search engine. – the busybee Jul 13 '22 at 08:07
You should use `execv()` rather than `execve()` unless you are going to provide a modified environment to the executed command. – Jonathan Leffler Jul 13 '22 at 13:33

How to use stderr with execve

0 Answers0