[pipe] Store pipe stream into buffer

code

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

int main()
{
    FILE *read_fp;
    char tmp[BUFSIZ + 1];
    char buffer[BUFSIZ + 1];    
    char macaddr_interface[18]={0};
    memset(buffer, '\0', sizeof(buffer));
    read_fp = popen("cat /home/freeman/test/test100/Interface0.txt  | awk 'NR >1  {print $1;}'", "r");

    if (read_fp != NULL) {
        while (fscanf(read_fp, "%s", macaddr_interface) != EOF)
        {
            /* - : Left-justify within the given field width */
            sprintf(tmp,"%-18s",macaddr_interface);
            strcat(buffer,tmp);
        }

        printf("%s",buffer);

        pclose(read_fp);
        exit(EXIT_SUCCESS);
    }
    exit(EXIT_FAILURE);
}

Result

00:22:15:4f:40:4b 08:00:27:6d:d4:1a 5c:ff:35:74:4c:5b 00:0c:29:3b:94:a4 

Reference:

1. C String Concatenation


2. printf