#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

void
cat(int f, char *s)
{
    char buf[8192];
    long n;

    while((n=read(f, buf, (long)sizeof buf))>0)
        if(write(1, buf, n)!=n)
        {
            printf("write error copying %s: %d\n", s, errno);
            exit(1);
        }
    if(n < 0)
    {
        printf("error reading %s: %d\n", s, errno);
        exit(1);
    }
}

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

    if(argc == 1)
        cat(0, "<stdin>");
    else for(i=1; i<argc; i++){
        f = open(argv[i], 0);
        if(f < 0)
        {
            printf("can't open %s: %d\n", argv[i], errno);
            exit(1);
        }
        else{
            cat(f, argv[i]);
            close(f);
        }
    }
    exit(0);
}