get environment variable

getenvaddr.c

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

int main(int argc, char *argv[]) {
    char *ptr;

    if (argc < 3) {
        printf("Usage: %s [environment] [path]\n", argv[0]);
        return 0;
    }

    ptr = getenv(argv[1]);
    ptr += (strlen(argv[0]) - strlen(argv[2])) * 2;
    printf("%s : %p\n", argv[1], ptr);

    return 0;
}