#include <stdio.h>

ttyin()
{
	char buf[BUFSIZ];
	FILE *tty;

	tty = fopen("/dev/tty", "r");
	if (fgets(buf, sizeof buf, tty) == NULL || buf[0] == 'q')
		exit(0);
	else
		return buf[0];
}

main()
{
	int c;
	char ans;
	char buf[BUFSIZ];

	fprintf(stderr, "%s", "swap nl with space (y/n)? ");
	ans = ttyin();
	if (ans == 'y' || ans == 'Y') {
		while(fgets(buf, sizeof buf, stdin) != NULL) {
			buf[strlen(buf)-1] = ' ';
			fputs(buf, stdout);
		}
		printf("\n");
	}
	else
		while((c = getchar()) != EOF)
			putchar(c);

	exit(0);
}