How to store an output from a UNIX command into a char with in C programming -

let's here code:

int main() {     char *number;     system("grep total myfile > filename");      printf(number); } 

this code finds line myfile containing "total" , outputs new file called filename. trying have output set char "number" directly, instead of having write/read filename. there way this?

thanks help!

if understand right title, want output command executed,

#include <stdio.h> #include <stdlib.h>  int main()  {     char number[100];     file *f = popen("echo 200", "r");     while (fgets(number, 100, f) != null) {         printf( "%s\n", number );     }     pclose(f);      return 0; } 

or want pass variable command , output variable

#include <stdio.h> #include <stdlib.h>  int main()  {     int n = 100;     char buf[100];     sprintf(buf, "echo %d > filename", n); // format command     system(buf);                           // execute     printf("%d\n", n);                     // print variable      return 0; }