Let's take a look at the Undo command also known as Command Z.
You can find it in almost every app on your Mac in the Edit menu, the first thing.
The shortcut is always Command Z.
It's so powerful.
A lot of us know its power but sort of take it for granted and others don't quite know
how powerful it is.
Like let's look at a very simple example.
Say you're typing something in any app and you make an edit.
You delete something.
You can go to Undo and replace it.
But a lot of people don't know that you can do multiple Undos.
So let's do a whole bunch of different edits here.
I've removed three lines.
I can Undo, Undo, Undo to put everything back.
Notice also there's a Redo command.
Usually a Shift Command Z.
So if you've undid like three steps and you want to go back one you can use Shift Command
Z and go forward again.
So this is a really simple example when you're typing.
But you can use Undo in all sorts of other cases.
So let's take a look at the Finder.
You can say select a file and delete it.
You can drag it to the Trash.
I'm just going to use Command Delete.
Now you could go into the Trash and find it and put it back.
But you can also use Undo to undo that.
It'll undo the move that file to the trash.
There it goes and puts it back inside the folder.
Now I can also Undo a regular move.
So I move this into this folder here.
Command Z returns it.
You can Undo multiple ones.
So I'll put this in Home.
I'll put this in Project A and I'll use Undo twice to go back two steps.
Every time you do something like that you can see what it is you're going to Undo by
going to the Edit menu.
So Undo That Move and then the Redo also tells you exactly what it's going to do.
So you don't have to guess what the Undo is going to do.
You can look in the Edit menu for that.
In the Finder you can also do things like Naming.
So let's rename this file, Another Name, and notice now I can Undo that rename.
So there are a lot of different things I can Undo in the Finder.
It's not just when you edit something or you move something.
How about Safari.
Now Safari is not somewhere where you create things generally.
You're just doing things.
So what could the Undo command possibly do for you.
Well, here I've got a window with three different tabs.
Let's say I'm going to close the middle tab there.
I realize I don't want to do that.
There's something I wanted on that page.
Well, Undo will undo that tab closing.
You can do multiple ones.
So I'll do those two there.
Undo close tab.
How about Mail.
Well, say you take a message here and you decide to archive it.
You can Undo that.
Or if you were to Delete it you can also Undo that.
Now what you can't Undo is sending an email because as soon as you send it, of course,
it goes from your Mac to a server and there's no way to pull it back.
But just about every app makes use of Undo.
Sometimes you can Undo multiple things and sometimes you can only undo one step.
So, for instance, we'll edit a photo here in Photos.
If I go to the adjustments here I can adjust say brilliance, exposure, highlight, shadows,
brightness, contrast and I can Undo each one individually.
Command Z, Command Z, back one step each.
But if I were to say leave an exposure difference there, go to filters, and apply a different
filter, and then also enhance, now you can see I can Undo the auto enhance, I can Undo
the filter, but I can't go beyond that.
There are some things once you exit out of here you can't Undo.
Likewise if we were to go back into TextEdit we could do all sorts of things like, for
instance, I could remove that piece of text, remove that piece of text, add some more and
you can see I can Undo each of those changes.
I can even Save and still Undo each of those changes.
But if I close the document and then open it again the Undos are gone.
So leaving the document, closing it and opening it up again, you loose that Undo history at
least with TextEdit and with most apps.