NUDGE(1) General Commands Manual NUDGE(1)

nudge — terminal vibrator

nudge [-f file] [-n count] [-s shake] [-t delay]

The nudge utility nudges the terminal. An xterm(1) compatible terminal is required.

The arguments are as follows:

file
Open the terminal named by file. The default is /dev/tty.
count
Set the number of times to nudge the terminal. The default is 2.
shake
Set the shake intensity in pixels. The default is 10.
delay
Set the interval between shakes in milliseconds. The default is 20.
September 4, 2020 OpenBSD 7.4

nudge.c in git 

/* Copyright (C) 2020  June McEnroe <june@causal.agency>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>

static int shake = 10;
static int delay = 20000;
static int count = 2;

static void move(int tty, int x, int y) {
	dprintf(tty, "\33[3;%d;%dt", x, y);
	usleep(delay);
}

int main(int argc, char *argv[]) {
	const char *path = "/dev/tty";
	for (int opt; 0 < (opt = getopt(argc, argv, "f:n:s:t:"));) {
		switch (opt) {
			break; case 'f': path = optarg;
			break; case 'n': count = atoi(optarg);
			break; case 's': shake = atoi(optarg);
			break; case 't': delay = atoi(optarg) * 1000;
			break; default:  return 1;
		}
	}

	int tty = open(path, O_RDWR);
	if (tty < 0) err(1, "%s", path);

	struct termios save;
	int error = tcgetattr(tty, &save);
	if (error) err(1, "tcgetattr");

	struct termios raw = save;
	cfmakeraw(&raw);
	error = tcsetattr(tty, TCSAFLUSH, &raw);
	if (error) err(1, "tcsetattr");

	char buf[256];
	dprintf(tty, "\33[13t");
	ssize_t len = read(tty, buf, sizeof(buf) - 1);
	buf[(len < 0 ? 0 : len)] = '\0';

	int x, y;
	int n = sscanf(buf, "\33[3;%d;%dt", &x, &y);

	error = tcsetattr(tty, TCSANOW, &save);
	if (error) err(1, "tcsetattr");
	if (n < 2) return 1;

	dprintf(tty, "\33[5t");
	for (int i = 0; i < count; ++i) {
		move(tty, x - shake, y);
		move(tty, x, y + shake);
		move(tty, x + shake, y);
		move(tty, x, y - shake);
		move(tty, x, y);
	}
}