title: dotnet ef migrations issue in Ubuntu 19.10. Dotnet sdk 3.1.1
body: <p>I installed <code>dotnet ef</code> tool in order to generate migrations for a dotnet core project am working on using the command. <code>dotnet tool install -g dotnet-ef</code>. The installation was successfull. In order to us <code>dotnet ef</code> i have installed the nuget packages below</p>
  
  <ol>
  <li>Microsoft.EntityFrameworkCore.SqlServer</li>
  <li>Microsoft.EntityFrameworkCore</li>
  <li>Microsoft.AspNetCore.Identity.EntityFrameworkCore</li>
  <li>Microsoft.EntityFrameworkCore.Tools</li>
  </ol>
  
  <p>When trying to generate migrations using the command <code>dotnet ef migrations add IdentityandCategory</code> i get the output below.</p>
  
  <pre><code>It was not possible to find any compatible framework version
  The framework 'Microsoft.NETCore.App', version '3.1.1' was not found.
    - The following frameworks were found:
        2.1.14 at [/usr/share/dotnet/shared/Microsoft.NETCore.App]
        2.2.8 at [/usr/share/dotnet/shared/Microsoft.NETCore.App]
        3.1.0 at [/usr/share/dotnet/shared/Microsoft.NETCore.App]
  
  You can resolve the problem by installing the specified framework and/or SDK.
  
  The specified framework can be found at:
    - https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&amp;framework_version=3.1.1&amp;arch=x64&amp;rid=ubuntu.19.10-x64
  </code></pre>
  
  <p>I reinstall dotnet 3.1.1 but this trouble continues. <code>dotnet info</code> seem to detect the version
  when i run <code>donet --info</code></p>
  
  <pre><code>.NET Core SDK (reflecting any global.json):
   Version:   3.1.100
   Commit:    cd82f021f4
  
  Runtime Environment:
   OS Name:     ubuntu
   OS Version:  19.10
   OS Platform: Linux
   RID:         ubuntu.19.10-x64
   Base Path:   /usr/share/dotnet/sdk/3.1.100/
  
  Host (useful for support):
    Version: 3.1.0
    Commit:  157910edee
  
  .NET Core SDKs installed:
    2.1.802 [/usr/share/dotnet/sdk]
    2.2.402 [/usr/share/dotnet/sdk]
    3.1.100 [/usr/share/dotnet/sdk]
  
  .NET Core runtimes installed:
    Microsoft.AspNetCore.All 2.1.14 [/usr/share/dotnet/shared/Microsoft.AspNetCore.All]
    Microsoft.AspNetCore.All 2.2.8 [/usr/share/dotnet/shared/Microsoft.AspNetCore.All]
    Microsoft.AspNetCore.App 2.1.14 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
    Microsoft.AspNetCore.App 2.2.8 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
    Microsoft.AspNetCore.App 3.1.0 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
    Microsoft.NETCore.App 2.1.14 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
    Microsoft.NETCore.App 2.2.8 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
    Microsoft.NETCore.App 3.1.0 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
  
  To install additional .NET Core runtimes or SDKs:
    https://aka.ms/dotnet-download
  </code></pre>
  
  <p>How can i solve this issues?  Thank in advance for your help</p>