Dev Blog

Practice ​

Example 1. Workout log: .gitignore, .gitattributes, restoring a file ​

Create a "Workout log" console program with a Workout record in a separate file and keep it in a Git repository. Show how to fix a commit that included the bin and obj folders, add a .gitattributes file, and restore an accidentally deleted file.

The Workout.cs file:

cs
namespace WorkoutLog;

public record Workout(DateOnly Date, string Kind, int Minutes);

The Program.cs file:

cs
using WorkoutLog;

Console.OutputEncoding = System.Text.Encoding.UTF8;

List<Workout> log =
[
    new(new DateOnly(2026, 9, 14), "Running", 30),
    new(new DateOnly(2026, 9, 16), "Swimming", 45),
];

foreach (Workout w in log)
{
    Console.WriteLine($"{w.Date:dd.MM} {w.Kind,-10} {w.Minutes,3} min");
}
Console.WriteLine($"Total: {log.Sum(w => w.Minutes)} min");
PS> dotnet run
14.09 Running     30 min
16.09 Swimming    45 min
Total: 75 min

After dotnet run, the project folder contains bin and obj. If you create a repository without .gitignore and run git add ., they end up in the commit: the Count property of the string array that PowerShell returns for the git ls-files output shows 27 files instead of three.

PS> git init
Initialized empty Git repository in D:/Labs/WorkoutLog/.git/

PS> git add .
PS> git commit -q -m "Create workout log"
PS> (git ls-files).Count
27

To fix the mistake, we create .gitignore, remove the folders from the index (but not from disk) with git rm -r --cached, and record both changes in one commit. The -q (quiet) option suppresses the long list of removed files:

PS> dotnet new gitignore
The template "dotnet gitignore file" was created successfully.
PS> git rm -r -q --cached bin obj
PS> git add .gitignore
PS> git commit -q -m "Stop tracking build output"
PS> git ls-files
.gitignore
Program.cs
Workout.cs
WorkoutLog.csproj

The build files have disappeared from the repository (but remain in the history of the first commit). Next, we add .gitattributes and check line endings: i/lf means LF in the index, and w/crlf means CRLF in the working file:

PS> dotnet new gitattributes
The template "dotnet gitattributes file" was created successfully.

PS> git add .gitattributes
PS> git commit -m "Add .gitattributes"
[main 7f3d4cb] Add .gitattributes
 1 file changed, 107 insertions(+)
 create mode 100644 .gitattributes
PS> git ls-files --eol
i/lf    w/crlf  attr/text=auto          .gitattributes
i/lf    w/crlf  attr/text=auto          .gitignore
i/lf    w/crlf  attr/text               Program.cs
i/lf    w/crlf  attr/text               Workout.cs
i/lf    w/crlf  attr/text=auto          WorkoutLog.csproj

Finally, we "accidentally" delete Workout.cs. The build now fails with error CS0246 (the WorkoutLog namespace cannot be found), and git status shows the deleted file (D). Since the file is in the last commit, git restore brings it back:

PS> git status --short
 D Workout.cs

PS> git restore Workout.cs
PS> git status
On branch main
nothing to commit, working tree clean

A file deleted several commits ago is restored from the required commit: git restore --source <commit> <file>.

Example 2. Exchange rates: git stash, git cherry-pick, git rebase ​

The "Exchange rates" program converts an amount in hryvnias (a command-line argument, 1000 by default) into other currencies. In the first version, the euro rate was entered incorrectly (4.78m instead of 47.80m). A developer is reworking the output into a table in the feature/table branch when a bug report arrives. You need to: stash the unfinished work, fix the bug in main, continue working in the branch, move only the README.md file from the branch into main, and rebase the branch onto the updated main.

PS> git switch -c feature/table
Switched to a new branch 'feature/table'

PS> git status --short
 M Program.cs

PS> git stash push -m "Table output"
Saved working directory and index state On feature/table: Table output
PS> git switch main
Switched to branch 'main'

The working directory is clean, so in main we fix the rate and commit, and then restore the stash:

PS> git commit -am "Fix EUR rate"
[main 5c0d352] Fix EUR rate
 1 file changed, 1 insertion(+), 1 deletion(-)

PS> git switch feature/table
Switched to branch 'feature/table'
PS> git stash pop
On branch feature/table
...
Dropped refs/stash@{0} (d5f600ba3180c5add08bf9c3f1dc960cea590d61)

PS> git commit -am "Print rates as table"
[feature/table c143403] Print rates as table
 1 file changed, 3 insertions(+), 1 deletion(-)

A README.md file describing how to run the program was also created in the branch. It is needed in main right now, so we move only this commit. A branch name used this way means its latest commit:

PS> git add README.md
PS> git commit -m "Add README"
[feature/table 95faaef] Add README
 1 file changed, 3 insertions(+)
 create mode 100644 README.md

PS> git switch main
Switched to branch 'main'
PS> git cherry-pick feature/table
[main 789b9d2] Add README
 Date: Thu Sep 17 10:35:11 2026 +0300
 1 file changed, 3 insertions(+)
 create mode 100644 README.md

For the branch to contain the fixed rate, we rebase it onto main. Git notices that the Add README commit is already in main (as 789b9d2) and skips it, so only the table remains in the branch:

PS> git switch feature/table
Switched to branch 'feature/table'

PS> git rebase main
warning: skipped previously applied commit 95faaef
hint: use --reapply-cherry-picks to include skipped commits
...
Successfully rebased and updated refs/heads/feature/table.
PS> git log --oneline --graph --all
* 946dc78 Print rates as table
* 789b9d2 Add README
* 5c0d352 Fix EUR rate
* be5ce53 Create currency converter

The history is now linear. After git switch main and git merge feature/table, the branch is merged with a fast-forward. The program with the table and the fixed rate:

PS> dotnet run -- 5000
Amount: 5,000.00 UAH
Currency      Rate      You get
USD          41.25       121.21
EUR          47.80       104.60
PLN          11.20       446.43

Example 3. Working in pairs: a bare repository, branch review, a conflict, and a release ​

Two students (Olena and Andrii) are developing an "Office hours schedule" program together. The shared repository is a bare repository on disk, and each team member has their own clone. Andrii adds a room number in a branch, and Olena reviews and merges the branch, resolves a conflict, and releases version 1.0.0.

The program prints the heading "OOP office hours:" and, for each day in the array string[] days = ["Monday", "Wednesday", "Friday"];, the line Console.WriteLine($"{day}: 14:00–15:00");.

Olena creates a bare repository and pushes the first commit:

PS> git init --bare D:\Labs\remote\Consultations.git
Initialized empty Git repository in D:/Labs/remote/Consultations.git/

PS> git remote add origin D:\Labs\remote\Consultations.git
PS> git push -u origin main
To D:\Labs\remote\Consultations.git
 * [new branch]      main -> main
branch 'main' set up to track 'origin/main'.

Andrii clones the repository into his folder, sets his name in the clone (git config user.name, git config user.email), changes the output line to "{day}: 14:00–15:00, room 305" in a branch, and pushes it:

PS> git clone D:\Labs\remote\Consultations.git
Cloning into 'Consultations'...
done.

PS> git switch -c feature/room
Switched to a new branch 'feature/room'
PS> git commit -am "Show room number"
[feature/room 2ddd122] Show room number
 1 file changed, 1 insertion(+), 1 deletion(-)

PS> git push -u origin feature/room
To D:\Labs\remote\Consultations.git
 * [new branch]      feature/room -> feature/room
branch 'feature/room' set up to track 'origin/feature/room'.

Meanwhile, Olena added the teacher's name to the same line in main and pushed the commit. Now she fetches Andrii's branch and reviews it:

PS> git commit -am "Show teacher name"
[main a7f2b7c] Show teacher name
 1 file changed, 1 insertion(+), 1 deletion(-)

PS> git push
To D:\Labs\remote\Consultations.git
   423bf38..a7f2b7c  main -> main
PS> git fetch
From D:\Labs\remote\Consultations
 * [new branch]      feature/room -> origin/feature/room

PS> git log --oneline main..origin/feature/room
2ddd122 Show room number

The git diff main...origin/feature/room command shows the branch's only change—the output line with the room number.

The changes are accepted, but the merge stops with a conflict because both team members changed the same line:

PS> git merge origin/feature/room
Auto-merging Program.cs
CONFLICT (content): Merge conflict in Program.cs
Automatic merge failed; fix conflicts and then commit the result.
cs
foreach (string day in days)
{
<<<<<<< HEAD
    Console.WriteLine($"{day}: 14:00–15:00 (Koval O.)");
=======
    Console.WriteLine($"{day}: 14:00–15:00, room 305");
>>>>>>> origin/feature/room
}

Olena keeps both changes in a single line: Console.WriteLine($"{day}: 14:00–15:00, room 305 (Koval O.)");. You can do the same in Visual Studio: Git Changes → Unmerged Changes, double-click Program.cs, select both fragments in the merge editor, edit the line in the Result pane, and click Accept Merge. Next come the merge commit and a check:

PS> git add Program.cs
PS> git commit --no-edit
[main a6af62f] Merge remote-tracking branch 'origin/feature/room'

PS> dotnet run
OOP office hours:
Monday: 14:00–15:00, room 305 (Koval O.)
Wednesday: 14:00–15:00, room 305 (Koval O.)
Friday: 14:00–15:00, room 305 (Koval O.)

For the release, Olena creates a CHANGELOG.md file with the heading "Changelog" and a "1.0.0 – 2026-09-17" section listing the version's features, commits it, adds an annotated tag, and pushes main together with the tag (--follow-tags), and then deletes the merged branch on the server:

PS> git add CHANGELOG.md
PS> git commit -m "Add changelog for 1.0.0"
[main 848bdd1] Add changelog for 1.0.0
 1 file changed, 6 insertions(+)
 create mode 100644 CHANGELOG.md
PS> git tag -a v1.0.0 -m "Release 1.0.0"
PS> git push --follow-tags
To D:\Labs\remote\Consultations.git
   a7f2b7c..848bdd1  main -> main
 * [new tag]         v1.0.0 -> v1.0.0

PS> git push origin --delete feature/room
To D:\Labs\remote\Consultations.git
 - [deleted]         feature/room
PS> git log --oneline --graph
* 848bdd1 Add changelog for 1.0.0
*   a6af62f Merge remote-tracking branch 'origin/feature/room'
|\
| * 2ddd122 Show room number
* | a7f2b7c Show teacher name
|/
* 423bf38 Create consultation schedule

Andrii updates his clone with git pull (a fast-forward to 848bdd1 together with the v1.0.0 tag), deletes the merged local branch with git branch -d feature/room, and removes the reference to the deleted remote branch with git fetch --prune.