Create desktop file to see freespace
You need gnome terminal to create editable profile.
Open terminal and run
df -h
to see free space and identify the name of your system partition.
Lets say your system partition is /devsda5.
Then, create a desktop file with the content:
[Desktop Entry]
Name=Show free spacce
Comment=Show free space
Exec=gnome-terminal --window-with-profile=new1 -e "df -h /dev/sda5"
Icon=gnome-disks
Terminal=false
Type=Application
StartupNotify=true
Categories=GNOME;GTK;Settings;HardwareSettings;X-GNOME-Settings-Panel;System;
Save it to usr/share/applications and make it executable. Now you can run it from search.
To see space on all partitions, just use this line:
Exec=gnome-terminal --window-with-profile=new1 -e "df -h"
alternative link download