coreutils/src/yes.c

#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[]) {
	char *output = "y";
	if (argc >= 1) {
		while (1) {
			for (int i = 1; i < argc; i++)
				printf("%s ", argv[i]);
			printf("\n");
		}
	} else {
		while (1) {
			printf("%s\n", output);
		}
	}
}