How to inject keystrokes via a shell script?

Question

I'm trying to inject keystrokes into the input daemon so as to simulate typing from a Bash script. Is this possible, and if so, how can I make it happen?

Answer 1

If you are operating at the X level (as in Gilles' question), then use xdotool like so:

xdotool key KEYSTROKE_SPECIFIER

Where KEYSTROKE_SPECIFIER can be something like "a" or "F2" or "control+j"

EDIT: I missed your response to Gilles' question, sorry. I'll leave this response here as a solution for the X-case.

Answer 2

Use the uinput driver. I don't think there's a utility for that; you're going to have to write or adapt a bit of C code. In a nutshell:

#include <fcntl.h>
#include <ioctl.h>
#include <unistd.h>
#include <linux/input.h>
#include <linux/uinput.h>
/* Set up a fake keyboard device */
fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK); // or /dev/input/uinput
ioctl(fd, UI_SET_EVBIT, EV_KEY);
struct uinput_user_dev uidev = …;
write(fd, &uidev, sizeof(uidev));
ioctl(fd, UI_DEV_CREATE);
/* Send an event */
struct input_event ev = …;
write(fd, &ev, sizeof(ev));
/* Clean up */
ioctl(fd, UI_DEV_DESTROY);
close(fd);

More complete references:

• Using uinput driver in Linux-2.6.x to send user input, by Mehul Patel
• Gettig started with uinput, by Gregory Thiemonge

Answer 3

I wrote some Python code that does that. You can find it in my open source project.

http://code.google.com/p/pycopia/source/browse/trunk/core/pycopia/OS/Linux/event.py

If you run that module as a script as root you can see a demo in action.

This basic functionality was extended for another project, powerdroid, that provides more concrete implementation for an embedded system (Android).

http://code.google.com/p/powerdroid/source/browse/trunk/src/droid/devices.py

Answer 4

If you're NOT working with X programs with windows that can be sent keys, you are probably looking for expect, a handy and very configurable program for running other interactive shell programs as if a user were controlling the terminal. You can setup programatic responses to respond to various output with different inputs.