NBClassic Keyboard Shortcuts: Command and Dual-Mode

I'm taking inventory of all the Command Mode and dual-mode nbclassic keyboard shortcuts on macOS, with my random musings about each. This is part of my deliberate practice to master all of the useful ones, and will serve as a reference for myself later.

From Command Mode

Press Esc to get out of editing a cell (Edit Mode), then:

p: Open the Command Palette

This opens the little dialog with commands. Then you can press up or down arrows to select commands.

• There's a scroll bug so when you go down past the bottom edge, the whole window doesn't scroll. When I go past the bottom edge, I can only see command names and not their shortcuts. It basically means the commands not shown by default are hardly usable unless I already know them. The ones shown by default are also not that useful: I rarely want to press number keys to convert a cell to a heading when Markdown # is so easy.
• It would be nice if this dialog took up the whole screen. So much wasted space where I wish I could just see more commands. Beyond taking up the whole screen, it would be nice if it were multi-column so you could see tons of commands all at once.
• Oh! I can rename a notebook from here without using my mouse! That's game-changing for me.

Change cell type:

• M: Markdown. I use it often.
• Y: Code. I use it often, but I usually accidentally type C instead of Y. Y on the other hand feels like it should yank, which is sort of what C does.
• R: Raw. I've never used this. Let's try it now. Oh, that's a good one.
  • Probably useful for frontmatter in blog apps that require it. This may actually be one of the key pieces that ends up converting me over to the frontmatter side.
  • Occasionally I have other code that I want to stick into a notebook without it being interpreted, and I use fenced no-syntax code blocks within Markdown to do it. Advent of Code puzzle inputs come to mind, stuff like: aa bb cc d e e f: Find and replace. I've never used this. I always use Cmd F and use Chrome or Firefox's search. I'm trying it. That's cool that it can take regular expressions! I tried \w+ and that was fun. To get those to work, I had to toggle the button off and then on again.

k or Up arrow: Select previous cell

j or Down arrow: Select next cell

• I always use the arrows, never k and j, but I'll try them since they're nice Vim workalikes.

Shift k or Shift Up arrow: Add previous cell to selection

Shift j or Shift Down arrow: Add next cell to selection

• I use Shift with up and down arrows sometimes. I didn't know I could use those with k and j. I'll try to use those.
• "Extend selected cells" in the docs didn't make sense to me until I tried it.

Cmd a: Select all cells. I never use this and it seems not very useful. Could I be wrong? Copy-pasting cells between notebook browser tabs doesn't work for me, and it may be related to that use case.

a / b: Insert cell above/below. I use this often.

Copy-pasting:

• x / c / v: Cut/copy/paste selected cells. I use this often.
• Shift v: Paste above current cell. I never use this but it feels incredibly useful.
• Cmd v: Dialog for paste from system clipboard. Sometimes I accidentally press this. I never use this deliberately, because pasting from my system clipboard into Edit Mode works fine. Would I want to paste in Command Mode? I'll look out for the opportunity. Oh wait, this looks like it would be useful in conjunction with Cmd a to bring a whole notebook over into a new one.

d then d again: Delete cell. I mostly use x instead of this, out of muscle memory not intentionality.

z: Undo cell deletion. This usually doesn't work for me because I press x. I can press Shift v when that happens, I now know.

Shift m: Merge cells. I occasionally do this by accident.

• Every time that happens, I think, "Oh, that's useful, I should do that on purpose sometimes." Then I try to undo with z and it doesn't work, because z only undoes dd. Then I re-split the cells with Ctrl Shift -.
• But I never actually do it on purpose. My need to merge cells these days is rare enough that I don't remember this. I suppose with imports maybe it'll be good.
• That's cool that if you have only 1 cell selected, it'll merge with the next cell.

s or Ctrl s: Save and checkpoint. I use Ctrl s often. I didn't realize s does the same exact thing. That saves my pinky a bit.

l: Toggle line numbers. I rarely use this other than when Danny asks me to turn the line numbers on.

o: Toggle output of selected cells. I never use this, but I'll try it now on the time cell. Okay, I could see that being useful if a cell's output is huge, I can't truncate it, and the output iframe doesn't turn on, which happens occasionally for me.

Shift o: Toggle output scrolling of selected cells. I never use this. Maybe it'll solve my pain point of not being able to see the full version via keyboard of an iframe-truncated output. Oh, wow, I'll use this all the time now that I know about it. Wow, this would have saved me a lot of trackpad scrolling pain yesterday.

Kernel problem sequences:

• i then i: Interrupt the kernel. I never use this but plan to. But AI tells me it's essential to stop deep learning training runs early, or to stop overfitting as soon as I see it happening. Yeah, I'll try that then.
• 0 then 0: Restart the kernel. I rarely use this but should do it more.

Commands I don't understand, or that are broken for me, possibly due to my customizations or nbextensions:

• Esc or q from Command Mode to "Close the pager". Does that mean to close Command Palette? If I have Command Palette open, that's what it does. If I have regular Command Mode open, it doesn't seem to do anything.
• h: The docs say it'll "show keyboard shortcuts", but nothing shows for me.

From Both Modes

Running cells:

• Shift Enter: Run the current cell and create a new one below, or select the existing one below. I use this often. "Run cell, select below" in the docs isn't quite right.
• Cmd Enter or Ctrl Enter: Run the current cell, keep it selected, and switch to Command Mode if not already there. I never use this.
  • I sort of like it better than my current habit of Esc then Shift Enter, so I'll start using it.
  • Oh, that's also cool that you can multi-select cells via keyboard and run them all. After you do that, the last cell gets selected.

Cells for Testing

print(datetime.now().strftime('%I:%M:%S %p'))

Here I print the time in a test cell. That way I can see if the cell is actually run.

[i for i in range(1000)]

Here's a cell with long output, to test Shift o.