Powershell Script to add Code Analysis and Style Cop to all your .NET Core Projects.

addcasa.ps1

# Place the script in the solution folder
# Add the ca.ruleset to the solution folder
# Run the Powershell Script to add Code Analysis and StyleCop to all your .NET Core Projects.
$projects = (Get-ChildItem . -recurse) | Where-Object {$_.extension -eq ".csproj"}
foreach ($project in $projects) {
    $content = Get-Content $project.FullName
    if (!($content | Select-String -pattern "<CodeAnalysisRuleSet>ca.ruleset</CodeAnalysisRuleSet>")) {
        $content = $content.Replace("</Project>", "`t<PropertyGroup>`r`n`t`t<CodeAnalysisRuleSet>ca.ruleset</CodeAnalysisRuleSet>`r`n`t</PropertyGroup>`r`n</Project>")
        $content | Out-File $project.FullName -Encoding Default
    }
    dotnet add $project.FullName package Microsoft.CodeAnalysis.FxCopAnalyzers
    dotnet add $project.FullName package StyleCop.Analyzers
    Copy-Item ".\ca.ruleset" -Destination "$($project.Directory.FullName)\ca.ruleset"
}
dotnet restore

ca.ruleset

<?xml version="1.0" encoding="utf-8"?>
<RuleSet Name="Custom Rulset" Description="Custom Rulset" ToolsVersion="14.0">
    <Rules AnalyzerId="AsyncUsageAnalyzers" RuleNamespace="AsyncUsageAnalyzers">
        <Rule Id="UseConfigureAwait" Action="Warning" />
    </Rules>
    <Rules AnalyzerId="Microsoft.Analyzers.ManagedCodeAnalysis" RuleNamespace="Microsoft.Rules.Managed">
        <Rule Id="CA1001" Action="Warning" />
        <Rule Id="CA1009" Action="Warning" />
        <Rule Id="CA1016" Action="Warning" />
        <Rule Id="CA1033" Action="Warning" />
        <Rule Id="CA1049" Action="Warning" />
        <Rule Id="CA1060" Action="Warning" />
        <Rule Id="CA1061" Action="Warning" />
        <Rule Id="CA1063" Action="Warning" />
        <Rule Id="CA1065" Action="Warning" />
        <Rule Id="CA1301" Action="Warning" />
        <Rule Id="CA1400" Action="Warning" />
        <Rule Id="CA1401" Action="Warning" />
        <Rule Id="CA1403" Action="Warning" />
        <Rule Id="CA1404" Action="Warning" />
        <Rule Id="CA1405" Action="Warning" />
        <Rule Id="CA1410" Action="Warning" />
        <Rule Id="CA1415" Action="Warning" />
        <Rule Id="CA1821" Action="Warning" />
        <Rule Id="CA1900" Action="Warning" />
        <Rule Id="CA1901" Action="Warning" />
        <Rule Id="CA2002" Action="Warning" />
        <Rule Id="CA2100" Action="Warning" />
        <Rule Id="CA2101" Action="Warning" />
        <Rule Id="CA2108" Action="Warning" />
        <Rule Id="CA2111" Action="Warning" />
        <Rule Id="CA2112" Action="Warning" />
        <Rule Id="CA2114" Action="Warning" />
        <Rule Id="CA2116" Action="Warning" />
        <Rule Id="CA2117" Action="Warning" />
        <Rule Id="CA2122" Action="Warning" />
        <Rule Id="CA2123" Action="Warning" />
        <Rule Id="CA2124" Action="Warning" />
        <Rule Id="CA2126" Action="Warning" />
        <Rule Id="CA2131" Action="Warning" />
        <Rule Id="CA2132" Action="Warning" />
        <Rule Id="CA2133" Action="Warning" />
        <Rule Id="CA2134" Action="Warning" />
        <Rule Id="CA2137" Action="Warning" />
        <Rule Id="CA2138" Action="Warning" />
        <Rule Id="CA2140" Action="Warning" />
        <Rule Id="CA2141" Action="Warning" />
        <Rule Id="CA2146" Action="Warning" />
        <Rule Id="CA2147" Action="Warning" />
        <Rule Id="CA2149" Action="Warning" />
        <Rule Id="CA2200" Action="Warning" />
        <Rule Id="CA2202" Action="Warning" />
        <Rule Id="CA2207" Action="Warning" />
        <Rule Id="CA2212" Action="Warning" />
        <Rule Id="CA2213" Action="Warning" />
        <Rule Id="CA2214" Action="Warning" />
        <Rule Id="CA2216" Action="Warning" />
        <Rule Id="CA2220" Action="Warning" />
        <Rule Id="CA2229" Action="Warning" />
        <Rule Id="CA2231" Action="Warning" />
        <Rule Id="CA2232" Action="Warning" />
        <Rule Id="CA2235" Action="Warning" />
        <Rule Id="CA2236" Action="Warning" />
        <Rule Id="CA2237" Action="Warning" />
        <Rule Id="CA2238" Action="Warning" />
        <Rule Id="CA2240" Action="Warning" />
        <Rule Id="CA2241" Action="Warning" />
        <Rule Id="CA2242" Action="Warning" />
        <Rule Id="CA1012" Action="Warning" />
    </Rules>
    <Rules AnalyzerId="StyleCop.Analyzers" RuleNamespace="StyleCop.Analyzers">
        <Rule Id="SA1305" Action="Warning" />
        <Rule Id="SA1412" Action="Warning" />
        <Rule Id="SA1600" Action="None" />
        <Rule Id="SA1609" Action="Warning" />
    </Rules>
</RuleSet>

You do not need to replicate the files.
you can remove line 13 and replace "ca.ruleset" by "$(SolutionDir)\ca.ruleset".

I got a build warning that cannot find ca.ruleset file. I think you need to also mention the file type. i.e. ca.ruleset.xml

You are right @GustavoAmerico I'll alos have to take a look to https://github.com/cmendible/dotnet-addcasa where I think I made the same thing...