If you are running Cinnamon you can open Nemo then right click inside and select Open as Root another instance of Nemo will open then navigate to the file and open it
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If you are running Xfce and Thunar you will have to add that function to the right click menu - open Thunar then go to Edit then down to "Configure custom actions" and open that "Custom Actions" will appear then click the Plus "+" button to add feature - "Create Action" will appear - in the Name block type in Open Root Here the Description block you can leave blank - under Command type in pkexec thunar %f you can pick an Icon if you want but is optional, now click on Appearance Conditions and put a check mark in Directories and Text Files click OK and exit out - Now close Thunar and re-open it now Right-Click your "Open as Root" should be there
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