Automator simulation of the mouse and keyboard
You can automate a mouse click using Applescript.

tell application "System Events"
    tell application process "Application_Name"
        key code 53
        delay 1
        click (click at {1800, 1200})
    end tell
end tell




If you want to click within a browser window you can use Applescript with the help of Javascript

tell application "safari"
    activate
    do JavaScript "document.getElementById('element').click();"
end tell




Purely via terminal, you can create a textfile with the name click.m or whatever name you like, save it with the following code

#import &lt;Foundation/Foundation.h&gt;
#import &lt;ApplicationServices/ApplicationServices.h&gt;

int main(int argc, char *argv[]) {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSUserDefaults *args = [NSUserDefaults standardUserDefaults];

    int x = [args integerForKey:@"x"];
    int y = [args integerForKey:@"y"];

    CGPoint pt;
    pt.x = x;
    pt.y = y;

    CGPostMouseEvent( pt, 1, 1, 1 );
    CGPostMouseEvent( pt, 1, 1, 0 );

    [pool release];
    return 0;
}


then compile it:

gcc -o click click.m -framework ApplicationServices -framework Foundation


and move it to the appropriate system folder

sudo mv click /usr/bin
sudo chmod +x /usr/bin/click


and now you can run a simple terminal command to manipulate the mouse

click -x [coord] -y [coord]




Other scripts you could use include MouseTools or xdotool; both of which are open-source.