# dotnetsay .NET Tool Sample
This sample demonstrates how to use and create .NET Tools. It works on Windows, macOS and Linux.
You must have the .NET SDK installed. [.NET Core 3.1](https://dotnet.microsoft.com/download/dotnet/3.1) is recommended.
## Installation
You can quickly install and try the [dotnetsay](https://www.nuget.org/packages/dotnetsay/):
```console
dotnet tool install -g dotnetsay
dotnetsay
```
> Note: You may need to open a new command/terminal window the first time you install a tool.
You can uninstall the tool using the following command.
```console
dotnet tool uninstall -g dotnetsay
```
Also see [dotnet-runtimeinfo](../dotnet-runtimeinfo/README.md).
## Build the Tool from source
You can build and package the tool using the following commands. The instructions assume that you are in the root of the repository.
```console
cd samples
cd dotnetsay
dotnet pack -c Release -o nupkg
dotnet tool install --add-source .\nupkg -g dotnetsay
dotnetsay
```
> Note: On macOS and Linux, `.\nupkg` will need be switched to `./nupkg` to accommodate for the different slash directions.
You can uninstall the tool using the following command.
```console
dotnet tool uninstall -g dotnetsay
```
The `PackAsTool` property in the [project file](dotnetsay.csproj) enables packing a console application as a global tool, as you can see in the following simplified example. Applications must target .NET Core 2.1 or higher for .NET Tools.
```xml
Exe
netcoreapp2.1
true
```
## Enabling Source Link with Tools
You can make tools and libraries debuggable with [Source Link](https://github.com/dotnet/sourcelink) by adding the following properties and `PackageReference`. The example is specific to git and GitHub. See [dotnet/sourcelink](https://github.com/dotnet/sourcelink) for other options.
```xml
true
embedded
true
```
When you or your users debug your binaries with Source Link, the debugger will attempt to retrieve content (like `.cs` files) from the recorded git commit in your binaries. The given commit needs to be published to a public or accessible private repo in order for that to work. This means that you should build from a branch whose commits are stable and already published. You can build from a PR branch, but the commits may not remain stable for long, as the PRs may be [squashed on merge](https://help.github.com/articles/about-pull-request-merges/).
For official builds, we recommend that you enable [`ContinuousIntegrationBuild`](https://github.com/dotnet/sourcelink/blob/main/docs/README.md#continuousintegrationbuild), so that the built artifacts are [reproducible and deterministic](https://reproducible-builds.org/) (same outcome independent of build machine or time).
The [dotnetsay project](dotnetsay.csproj) doesn't add these properties or the `PackageReference` but relies on the same information in the [Directory.Build.props](../Directory.Build.props) in the parent directory. The use of a Directory.Build.props is recommended for Source Link, to avoid maintaining these settings in multiple project files.
Source Link will fail if it cannot find a `.git` directory. This can happen if you build projects in containers at solution root and not repo root for example. There are solutions to that problem described at the [dotnet/sourcelink repo](https://github.com/dotnet/sourcelink).
## Debug Tools with Visual Studio
You can debug Source Link enabled .NET Tools with Visual Studio, using the `Developer Command Prompt for VS 2017`. The following example launches `dotnetsay` for debugging:
```console
devenv /debugexe c:\Users\rich\.dotnet\tools\dotnetsay.exe
```
Set `Debugger Type` to `Managed (CoreCLR)` in `Properties`. Then `Step Into new instance` from the `Debug` menu.
You will be asked if you want to download source from GitHub. After that, you will then be able to step through the execution of the tool.
