Xcode duplicate current line up/down

xcode-duplicate-line-up-down.md

Xcode duplicate line up/down

Bind keys to duplicate lines in Xcode

1. Open with text editor

/Applications/Xcode.app/Contents/Frameworks/IDEKit.framework/Versions/A/Resources/IDETextKeyBindingSet.plist

If you are using multiple versions of Xcode you have to open this file for each of them. Remember to change /Applications/Xcode.app to path where your Xcode is located.

2. Add thise lines:

<key>Duplication</key>
<dict>
    <key>Duplicate Current Line Up</key>
    <string>moveToBeginningOfLine:, deleteToEndOfLine:, yank:, insertNewline:, moveToBeginningOfLine:, yank:, moveUp:, moveToEndOfLine:</string>
    <key>Duplicate Current Line Down</key>
    <string>moveToBeginningOfLine:, deleteToEndOfLine:, yank:, insertNewline:, moveToBeginningOfLine:, yank:</string>
</dict>

3. Open Xcode and Xcode preferences ⌘ Command + , → Key Bindings and search for duplication

4. Click on Duplicate Current Line Up, add a shortcut for it, eg. (if you want same shortcut as visual studio code) ⌥ Option + ⇧ Shift + ↑ (remove any other bindings for this key)

5. Click on Duplicate Current Line Down, add a shortcut for it, eg. (if you want same shortcut as visual studio code) ⌥ Option + ⇧ Shift + ↓ (remove any other bindings for this key)

Thank you 🫡

@skarol do you know how to make this work when having selected multiple lines? It will only copy down/up the first selected line...

That's great, thank you!
Sadly, this doesn't cover the fact of duplicating whole blocks of code (@mesqueeb)

I started studying the code for such commands (https://developer.apple.com/documentation/appkit/nsstandardkeybindingresponding) and then asked AI, and I found out a bit how these works.

Apparently, deleteToEndOfLine: actually cuts the content into a "kill buffer", which yank: is able to read and paste from.

Btw, with some genuine help of Copilot, we came up with this solution, that includes both single lines and blocks.

    <key>Duplicate block Down</key>
    <string>selectLine:, copy:, moveRight:, paste:</string>
    <key>Duplicate block Up</key>
    <string>selectLine:, copy:, moveToBeginningOfLine:, paste:</string>

It seems to be working pretty good like this.