从C中的stdout输出系统命令

#include<stdio.h>
#include <stdlib.h>

int main() {
    FILE *fp;
    char path[1035];

    fp = popen("echo $PATH", "r");
    if (fp == NULL) {
        printf("Failed to run command\n" );
        exit(1);
    }

    while (fgets(path, sizeof(path)-1, fp) != NULL) {
        printf("%s", path);
    }

    pclose(fp);

    return 0;
}