# How to toggle visibility of all the evaluatable cells (but not their output)?

I know that I can select individual evaluatable cells and disable their Open property (through Cell > Cell Properties), but is there a simple way to toggle the Open status of all evaluatable cells?

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This, this and this may be helpful. –  bobthechemist Jul 25 '13 at 22:44
Something like this? (V9 only, because of Cells.)
toggleCellOpen[nb_: SelectedNotebook[]] :=