Is there a command to anchor everything?

Run this in the command bar. This will loop through every instance in workspace, nested search, and turn every parts anchored value to true.

function FindChildren(Object)
   for _,v in pairs(Object:GetChildren()) do
    if v:IsA("BasePart") then
        v.Anchored = true
    end
        FindChildren(v)
    end
end
FindChildren(workspace)