How to Specify Virtual Desktop for a Cron Task?

Bob P · Advocate Joined: 20 Oct 2004 Posts: 3370 Location: USA

I'm looking for some help writing a cron task that opens a browser instance and assigns it to appear on a specific virtual desktop in X11.

My window manager is KDE. So far I've been able to deploy the task, but I have had no luck designating the virtual desktop where I 'd like it to appear.

My KDE desktop has multiple virtual desktops that I can select with Pager. I'd like to restrict the specified task to appearing only on the specified virtual desktop. Right now I've got things working to the point that deploying the task works reliably, but the window manager is assigning the task to whichever virtual desktop happens to have focus, or to have recently had focus, rather than putting it on the virtual desktop I'd like it to be assigned to.

I'm using:
KDE Plasma 5.27.11
KDE FRameworks 5.116.0
Qt 5.15.14

Here's an example of a cron entry where I can call Brave Browser to open the Gentoo Forums home page:

sMueggli · Guru Joined: 03 Sep 2022 Posts: 460

Why are you using a cronjob for this task? I think XDG autostart is a better aproach to automatically start graphical applications.

Virtual desktops looks like a desktop specific thing. I do not think that cronjob and XDG autostart are aware of this.

Bob P · Advocate Joined: 20 Oct 2004 Posts: 3370 Location: USA

Thanks for responding.

My feeble undestanding of XDG Autostart is that it's used to:
a) autostart applications when the desktop is started, or
b) autostart applications when a drive is mounted

In my case, those events aren't correlated with the time that I want the application to be deployed. So I'm looking at BASH and cron.

I'm thinking there's got to be some way to communicate with the window manager to assign a virtual desktop ... I just haven't found it yet.

Thanks again.

szatox · Advocate Joined: 27 Aug 2013 Posts: 3389

Long long time ago KDE had an option in the config manager to bind an application to a workspace, is it still there?
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Ralphred · l33t Joined: 31 Dec 2013 Posts: 621

There are a few ways to do this, but both have implications regarding "interrupting" what you are doing when the job runs:

Use KDE's "special window settings/rules"
Easiest way to try this is let the task run, then right click the top left icon and use "special window settings" in the "more" menu.
The downside of this is with a browser the window title changes with once the page is loaded, so you might find it ignores "window title".
There are multiple options of when to apply the "desktop" property, but if you end up having to use "Force" and can't get the "window title" to work you'll confine all instances of Brave to the same desktop.
Use xdotool
There are two ways to use this, the first is simple, use xdotool to read the current active desktop, if it isn't the one brave is to spawn in, change to that (xdotool again), once it's spawned, change back.
The second way would be to have xdotool find the window after it's spawned, and use set_desktop_for_window to move it where it's supposed to be.

Below is a snippet from my media thingy, it starts the browser, waits for it to connect the amazon video site, then set focus on it so I can send the keystrokes for fullscreen etc.