How about doing it all in C?
Code:
#include<stdio.h>
#include<stdlib.h>
int main()
{
int min, sec;
char cmd[120];
printf ("How many minutes would you like to nap for?\n");
scanf("%d", &min);
sec = min * 60 ;
snprintf (cmd, 120, "rtcwake -m mem -s %d", sec);
system(cmd);
return 0;
}
