Configure a Linux workspace remotely from the command line
David Both 
Nearly everything can be done from the Linux command line, including remote configuration of desktops such as Xfce4.
One of the things I appreciate about Linux versus proprietary operating systems is that almost everything can be managed and configured from the command line. That means that nearly everything can be configured locally or even remotely via an SSH login connection. Sometimes it takes a bit of time spent on Internet searches, but if you can think of a task, it can probably be done from the command line.
The problem
Sometimes it is necessary to make remote modifications to a desktop using the command line. In this particular case, I needed to reduce the number of workspaces on the Xfce panel from four to three at the request of a remote user. This configuration only required about 20 minutes of searching on the Internet.
The default workspace count and many other settings for xfwm4 can be found and changed in the /usr/share/xfwm4/defaults file. So setting workspace_count=4 to workspace_count=2 changes the default for all users on the host. Also, the xfconf-query command can be run by non-root users to query and set various attributes for the xfwm4 window manager. It should be used by the user account that requires the change and not by root.
In the sample below, I have first verified the current setting of four workspaces, then set the number to two, and finally confirmed the new setting.
[user@test1 ~]# xfconf-query -c xfwm4 -p /general/workspace_count
4
[user@test1 ~]# xfconf-query -c xfwm4 -p /general/workspace_count -s 2
[user@test1 ~]# xfconf-query -c xfwm4 -p /general/workspace_count
2
[user@test1 ~]#This change takes place immediately and is visible to the user without a reboot or even logging out and back in. I had a bit of fun with this on my workstation by watching the workspace switcher change as I entered commands to set different numbers of workspaces. I get my amusements where I can these days. ;-)
More exploration
Now that I fixed the problem, I decided to explore the xfconf-query command in a bit more detail. Unfortunately, there are no man or info pages for this tool, nor is there any documentation in /usr/share. The usual fallback of using the -h option resulted in little helpful information.
$ xfconf-query -h
Usage:
xfconf-query [OPTION…] - Xfconf commandline utility
Help Options:
-h, --help Show help options
Application Options:
-V, --version Version information
-c, --channel The channel to query/modify
-p, --property The property to query/modify
-s, --set The new value to set for the property
-l, --list List properties (or channels if -c is not specified)
-v, --verbose Verbose output
-n, --create Create a new property if it does not already exist
-t, --type Specify the property value type
-r, --reset Reset property
-R, --recursive Recursive (use with -r)
-a, --force-array Force array even if only one element
-T, --toggle Invert an existing boolean property
-m, --monitor Monitor a channel for property changesThis is not a lot of help, but we can figure out a good bit from it anyway. First, channels are groupings of properties that can be modified. I made the change above to the general channel, and the property is workspace_count. Let’s look at the complete list of channels.
$ xfconf-query -l
Channels:
xfwm4
xfce4-keyboard-shortcuts
xfce4-notifyd
xsettings
xfdashboard
thunar
parole
xfce4-panel
xfce4-appfinder
xfce4-settings-editor
xfce4-power-manager
xfce4-session
keyboards
displays
keyboard-layout
ristretto
xfcethemer
xfce4-desktop
pointers
xfce4-settings-manager
xfce4-mixerThe properties for a given channel can also be viewed using the following syntax. I have used the less pager because the result is a long stream of data. I have pruned the listing below but left enough to see the type of entries you can expect to find.
$ xfconf-query -c xfwm4 -l | less
/general/activate_action
/general/borderless_maximize
/general/box_move
/general/box_resize
/general/button_layout
/general/button_offset
<SNIP>
/general/workspace_count
/general/workspace_names
/general/wrap_cycle
/general/wrap_layout
/general/wrap_resistance
/general/wrap_windows
/general/wrap_workspaces
/general/zoom_desktop
(END)You can explore all the channels in this manner. I discovered that the channels generally correspond to the various settings in the Settings Manager. The properties are the ones that you would set in those dialogs. Note that not all the icons you will find in the Settings Manager dialog window are part of the Xfce desktop, so there are no corresponding channels for them. The Screensaver is one example because it is a generic GNU screensaver and not unique to Xfce. The Settings Manager is just a good central place for Xfce to locate many of these configuration tools.
Documentation
As mentioned previously, there do not appear to be any man or info pages for the xconf-query command, and I found a lot of incorrect and poorly documented information on the Internet. The best documentation I found for Xfce4 is on the Xfce website, and some specific information on xconf-query can be found here.
