/* 
 * our_head.c -- a C program that prints the first L lines of its input,
 *   where L defaults to 10 but can be specified by the caller of the
 *   program.
 *
 *   (This program is inefficient and does not check its error
 *   conditions. It is meant to illustrate filters.)
 */
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>

int main(int argc, char** argv)
{
    int i = 0; 
    int nlines;
    char ch;
    int ret;

    if (argc == 2) {
	nlines = atoi(argv[1]);
    } else if (argc == 1) {
	nlines = 10;
    } else {
	fprintf(stderr, "usage: our_head [nlines]\n");
	exit(1);
    }

    for (i = 0; i < nlines; i++) {

	do {

	    /* read in the first character from fd 0 */
	    ret = read(0, &ch, 1);

	    /* if there are no more characters to read, then exit */
	    if (ret == 0) exit(0);

	    write(1, &ch, 1);

	} while (ch != '\n');

    }

    exit(0);
}