myhead

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

void incorrect_arg_fmt()
{
    fputs("incorrect arguments\n", stderr);
    abort();
}

int main(int argc, char **argv)
{
    int bytes = 2048;
    int just_read;
    void *buffer;

    if (argc == 2) {
        if (sscanf(argv[1], "%d", &bytes) != 1)
            incorrect_arg_fmt();
    } else if (argc != 1) {
        incorrect_arg_fmt();
    }

    buffer = malloc(bytes);

    while (bytes != 0 && (just_read = read(0, buffer, bytes)) != 0) {
        int delta;
        if (just_read < bytes)
            delta = just_read;
        else
            delta = bytes;
        bytes -= delta;
        write(1, buffer, delta);
    }
    free(buffer);
    return 0;
}