This is a discussion issue for aspnet/Announcements#290.

Update Feb. 28: Some clarification. This announcement was in regards to 2.1.300-preview2 versions of the CLI and up.

In 2.1.300-preview1, the following ASP.NET Core command line tools can be installed as a global command.

• dotnet watch
• dotnet user-secrets
• dotnet sql-cache

In 2.1 Preview 1, these commands are not pre-installed. You must use the dotnet install tool command to acquire them.

dotnet install tool dotnet-watch --global --version 2.1.0-preview1-final
dotnet install tool dotnet-dev-certs --global --version 2.1.0-preview1-final
dotnet install tool dotnet-user-secrets --global --version 2.1.0-preview1-final

If you have an existing project with a DotNetCliToolReference to the packages below, you must remove the DotNetCliToolReference in order to try the global version of the command.

• Microsoft.DotNet.Watcher.Tools (aka dotnet-watch)
• Microsoft.Extensions.SecretManager.Tools (aka dotnet-user-secrets)
• Microsoft.Extensions.Caching.SqlConfig.Tools (aka dotnet-sql-cache)

Prior to this release, these commands were only available if added to the MSBuild project as a DotNetCliToolReference and when executing "dotnet" in the project directory.
Once installed globally, the commands are available from any project directory.

Note: Using dotnet install tool will only apply to 2.1 Preview 1. Before we release the RTM version of 2.1, these will become built-in commands in the .NET Core CLI.
You won't need to use DotNetCliToolReference or dotnet install tool to acquire these commands. This is what aspnet/Announcements#290 was intended to communicate.