UNIX for Dummies Questions & Answers

#!/bin/sh

while [ 1 ]; do                        # Run for as long as nessesary
  if [ -f /some/where/a/file ]; then   # If filename exists and has the apropriate name
    echo "File is found"               # Notify and stop monitoring
    exit 0
  fi
  sleep 60                             # Else wait a minut and see again
done

#include <stdio.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>

int main(void)
{
  FILE* fp;
  time_t t;
  const char * file = "my_fifo_fil";
  if (mkfifo(file, 0644) == -1)
    {
      printf("Error initializing fifo    %s\n", file);
      return -1;
    }
  if(!(fp = fopen(file, "w")))
    {
      printf("Error opening fifo %s\n", file);
      return -1;
    }
  t = time(NULL);
  if(fprintf(fp,"Program Woken at: %s\n", ctime(&t)) < 0)
    {
      printf("Error printing to fifo %s\n", file);
      return -1;
    }
  printf("You woke me poking my fifo %s\n", file);
  if(close(fp) == -1)
    {
      printf("Error closing fifo %s\n", file);
      return -1;
    }
  if(unlink(file) == -1)
    {
      printf("Error unlinking fifo %s\n", file);
      return -1;
    }
  return 0;
}