I'm just finishing a pole barn. One end has a single sliding door. I need some ideas for a latch that I could open/close from the outside and inside. Doesn't have to lock, if I need to lock it I can do that easy enough from the inside and then go out the walk through door and lock it.

On the son's Morton building, you enter the walkthrough door, the sliding doors have cam latches that keep the doors from slapping in the wind. I do not know what type of sliding latch would hold the doors tight.

Give the slider a little wedge shape to it

What about a string and latch like the old time doors ,but put a hook on the latch so it catches a bar inside the door on the frame. Could use 1/16" wire rope instead of string.This is where the saying came from "I'll leave the latch string out for you" Some times simple is better

I thought about that Sore, I did not know how to word it. I bow to you.

Years ago,we had one on the outhouse door, when you went in,you pulled the string inside