Git worktree lesson

.gitignore

@@ -2,5 +2,6 @@ git_attributes
 *~
 *.swp
 **/exercise
+**/exercise-*
 **/remote
 .DS_Store

worktree/README.md

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+# Git Kata: Worktrees
+
+Git worktrees allow you to check out multiple branches of the same repository simultaneously in different directories.
+This is useful when you need to work on multiple features or branches at the same time without constantly switching branches
+or stashing changes.
+
+## Setup:
+
+1. Run `source setup.sh` (or `.\setup.ps1` in PowerShell)
+
+## The task
+
+You're working on a feature branch and need to make some changes. Instead of switching branches (which might require stashing changes), you'll use a worktree to work on the feature branch while keeping your main worktree on `master` clean.
+
+1. Explore the repository
+   1. What branch are you currently on?
+   2. What branches exist in this repository?
+   3. Use `git log --oneline --graph --all` to see the commit history
+   >*Notice that you have a `master` branch and a `feature` branch with different commits*
+
+2. Create a worktree for the feature branch
+   1. Use `git worktree add ../exercise-feature feature` to create a new worktree for the `feature` branch
+   2. Check where the new worktree was created (it should be at `../exercise-feature`, a sibling to the `exercise` directory)
+   3. Use `git worktree list` to see all worktrees
+   4. Navigate to the new worktree directory (`cd ../exercise-feature`) and verify you're on the `feature` branch
+
+3. Make changes in the worktree
+   1. While in the `exercise-feature` directory, create a new file called `new-feature.txt` with some content
+   2. Add and commit this file to the `feature` branch
+   3. Make another change - modify `feature.txt` and commit that change as well
+   4. Use `git log --oneline` to see your new commits on the `feature` branch
+
+4. Merge the feature branch into master
+   1. Navigate back to the main `exercise` directory (`cd ../exercise`)
+   2. Verify you're on the `master` branch
+   3. Merge the `feature` branch into `master` using `git merge feature`
+   4. Use `git log --oneline --graph` to see how the branches have been merged
+   5. Notice that you can see the commits you made in the worktree are now part of `master`
+
+5. Remove the worktree
+   1. Make sure you're in the `exercise` directory (the main worktree)
+   2. Use `git worktree remove ../exercise-feature` to remove the worktree
+   3. Verify it's been removed with `git worktree list`
+   4. Notice that the directory has been cleaned up automatically
+   5. The `feature` branch still exists - you can verify this with `git branch`
+
+## Useful commands
+
+- `git worktree add <path> <branch>` - Create a new worktree (typically as a sibling directory, e.g., `../exercise-feature`)
+- `git worktree list` - List all worktrees
+- `git worktree remove <path>` - Remove a worktree
+- `git worktree prune` - Clean up stale worktree references
+- `git merge <branch>` - Merge a branch into the current branch
+- `git branch` - List branches
+- `git log --oneline --graph --all` - View commit history
+- `git status` - Check repository status
+
+> **Note:** Worktrees are created as sibling directories to the main repository (e.g., `exercise-feature` next to `exercise`). The parent git repository's `.gitignore` includes patterns to ignore these worktree directories, keeping the exercise self-contained.

worktree/setup.ps1

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+. ..\utils\make-exercise-repo.ps1
+
+# Create initial commit on master
+Set-Content -Value "Initial content" -Path README.txt
+git add README.txt
+git commit -m "Initial commit on master"
+
+# Create feature branch with some commits
+git switch -c feature
+Set-Content -Value "Feature work" -Path feature.txt
+git add feature.txt
+git commit -m "Add feature.txt"
+
+Add-Content -Value "More feature work" -Path feature.txt
+git add feature.txt
+git commit -m "Update feature.txt"
+
+# Go back to master
+git switch master

worktree/setup.sh

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+#!/bin/bash
+
+# Include utils
+source ../utils/utils.sh
+
+kata="worktree"
+make-exercise-repo
+config-local-username
+
+# Create initial commit on master
+echo "Initial content" > README.txt
+git add README.txt
+git commit -m "Initial commit on master"
+
+# Create feature branch with some commits
+git switch -c feature
+echo "Feature work" > feature.txt
+git add feature.txt
+git commit -m "Add feature.txt"
+
+echo "More feature work" >> feature.txt
+git add feature.txt
+git commit -m "Update feature.txt"
+
+# Go back to master
+git switch master