Xcode - Duplicate Line key binding

Duplicate_Lines_in_Xcode_Keybinding.md

Key binding to duplicate lines in Xcode 11

Many posts and solutions add 3 different commands to IDETextKeyBindingSet.plist, but only Duplicate Lines is currently required.

1. Delete Line already exists in Xcode 11, just add a keybind to it.
2. Duplicate Current Line is not necessary because the solution bellow works correctly if the cursor is in a line or if multiple lines are selected. In both cases, it has some benefits over commands found in older posts: the clipboard is not touched, and a single undo reverts the change.

Steps

1. Open below directory in Finder with Cmnd + Shift + G

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

2. Open IDETextKeyBindingSet.plist with a text editor.

3. Add this in:

<key>Duplication</key>
<dict>
    <key>Duplicate Lines</key>
    <string>selectParagraph:, delete:, undo:, moveRight:, yankAndSelect:</string>
</dict>

4. Open Xcode and go to Xcode preferences -> Key Bindings -> Text tab -> Scroll till you see Duplication

5. Click on Duplicate Lines, add a shortcut for it, eg. Cmd + D (remove any other bindings for this key)

Credit

The code for the solution above was found on this StackOverflow post in the answer proposed by Rychu.