Added Get-FileEncoding cmdlet

.gitignore

@@ -8,3 +8,5 @@ project.lock.json
 Microsoft.PowerShell.TextUtility.xml
 # VSCode directories that are not at the repository root
 /**/.vscode/
+# Visual Studio IDE directory
+.vs/

README.md

@@ -20,6 +20,10 @@ Return a base64 encoded representation of a string.
 
 This will convert tabular data and convert it to an object.
 
+## Get-FileEncoding
+
+This cmdlet returns encoding for a file.
+
 ## Code of Conduct
 
 Please see our [Code of Conduct](.github/CODE_OF_CONDUCT.md) before participating in this project.

TextUtility.sln

@@ -0,0 +1,30 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.5.002.0
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{CBF81F7C-6E0A-4695-AA0F-35C61676B7EB}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.PowerShell.TextUtility", "src\code\Microsoft.PowerShell.TextUtility.csproj", "{B5249E6A-DBD6-49AD-B78B-DFF09CB9D26F}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{B5249E6A-DBD6-49AD-B78B-DFF09CB9D26F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B5249E6A-DBD6-49AD-B78B-DFF09CB9D26F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B5249E6A-DBD6-49AD-B78B-DFF09CB9D26F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B5249E6A-DBD6-49AD-B78B-DFF09CB9D26F}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(NestedProjects) = preSolution
+		{B5249E6A-DBD6-49AD-B78B-DFF09CB9D26F} = {CBF81F7C-6E0A-4695-AA0F-35C61676B7EB}
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {EAC68D5E-4DA0-4F37-88B6-CAF32652C01F}
+	EndGlobalSection
+EndGlobal

src/Microsoft.PowerShell.TextUtility.psd1

@@ -13,7 +13,7 @@
     PowerShellVersion = '5.1'
     FormatsToProcess = @('Microsoft.PowerShell.TextUtility.format.ps1xml')
     CmdletsToExport = @(
-        'Compare-Text','ConvertFrom-Base64','ConvertTo-Base64',"ConvertFrom-TextTable"
+        'Compare-Text','ConvertFrom-Base64','ConvertTo-Base64',"ConvertFrom-TextTable","Get-FileEncoding"
     )
     PrivateData = @{
         PSData = @{

src/code/GetFileEncodingCommand.cs

@@ -0,0 +1,70 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.IO;
+using System.Management.Automation;
+using System.Text;
+
+namespace Microsoft.PowerShell.TextUtility
+{
+    /// <summary>
+    /// This class implements the Get-FileEncoding command.
+    /// </summary>
+    [Cmdlet(VerbsCommon.Get, "FileEncoding", DefaultParameterSetName = PathParameterSet)]
+    [OutputType(typeof(Encoding))]
+    public sealed class GetFileEncodingCommand : PSCmdlet
+    {
+        #region Parameter Sets
+
+        private const string PathParameterSet = "ByPath";
+        private const string LiteralPathParameterSet = "ByLiteralPath";
+
+        #endregion
+
+        #region Parameters
+
+        /// <summary>
+        /// Gets or sets path from from which to get encoding.
+        /// </summary>
+        [Parameter(Position = 0, Mandatory = true, ValueFromPipeline = true, ValueFromPipelineByPropertyName = true, ParameterSetName = PathParameterSet)]
+        public string Path { get; set; }
+
+        /// <summary>
+        /// Gets or sets literal path from which to get encoding.
+        /// </summary>
+        [Parameter(Position = 0, Mandatory = true, ValueFromPipeline = true, ValueFromPipelineByPropertyName = true, ParameterSetName = LiteralPathParameterSet)]
+        [Alias("PSPath", "LP")]
+        public string LiteralPath
+        {
+            get
+            {
+                return _isLiteralPath ? Path : null;
+            }
+
+            set
+            {
+                Path = value;
+                _isLiteralPath = true;
+            }
+        }
+
+        private bool _isLiteralPath;
+
+        #endregion
+
+        /// <summary>
+        /// Process paths to get file encoding.
+        /// </summary>
+        protected override void ProcessRecord()
+        {
+            string resolvedPath = PathUtils.ResolveFilePath(Path, this, _isLiteralPath);
+
+            if (!File.Exists(resolvedPath))
+            {
+                PathUtils.ReportPathNotFound(Path, this);
+            }
+
+            WriteObject(PathUtils.GetPathEncoding(resolvedPath));
+        }
+    }
+}

src/code/Microsoft.PowerShell.TextUtility.csproj

@@ -17,7 +17,7 @@
         <PackageReference Include="PowerShellStandard.Library" Version="5.1.0-*">
             <PrivateAssets>all</PrivateAssets>
         </PackageReference>
-        <PackageReference Include="System.Text.Json" Version="6.0.6" >
+        <PackageReference Include="System.Text.Json" Version="6.0.6">
             <PrivateAssets>all</PrivateAssets>
         </PackageReference>
     </ItemGroup>
@@ -28,4 +28,19 @@
         </Content>
     </ItemGroup>
 
+    <ItemGroup>
+      <Compile Update="Resources\PathUtilityStrings.Designer.cs">
+        <DesignTime>True</DesignTime>
+        <AutoGen>True</AutoGen>
+        <DependentUpon>PathUtilityStrings.resx</DependentUpon>
+      </Compile>
+    </ItemGroup>
+
+    <ItemGroup>
+      <EmbeddedResource Update="Resources\PathUtilityStrings.resx">
+        <Generator>ResXFileCodeGenerator</Generator>
+        <LastGenOutput>PathUtilityStrings.Designer.cs</LastGenOutput>
+      </EmbeddedResource>
+    </ItemGroup>
+
 </Project>

src/code/PathUtils.cs

@@ -0,0 +1,115 @@
+using System;
+using System.Collections.ObjectModel;
+using System.Globalization;
+using System.IO;
+using System.Management.Automation;
+using System.Text;
+using Microsoft.PowerShell.TextUtility.Resources;
+
+namespace Microsoft.PowerShell.TextUtility
+{
+    /// <summary>
+    /// Defines generic path utilities and helper methods for TextUtility.
+    /// </summary>
+    internal static class PathUtils
+    {
+        /// <summary>
+        /// Resolves user provided path using file system provider.
+        /// </summary>
+        /// <param name="path">The path to resolve.</param>
+        /// <param name="command">The command.</param>
+        /// <param name="isLiteralPath">True if the wildcard resolution should not be attempted.</param>
+        /// <returns>The resolved (absolute) path.</returns>
+        internal static string ResolveFilePath(string path, PSCmdlet command, bool isLiteralPath)
+        {
+            string resolvedPath;
+
+            try
+            {
+                ProviderInfo provider = null;
+                PSDriveInfo drive = null;
+
+                PathIntrinsics sessionStatePath = command.SessionState.Path;
+
+                if (isLiteralPath)
+                {
+                    resolvedPath = sessionStatePath.GetUnresolvedProviderPathFromPSPath(path, out provider, out drive);
+                }
+                else
+                {
+                    Collection<string> filePaths = sessionStatePath.GetResolvedProviderPathFromPSPath(path, out provider);
+
+                    if (!provider.Name.Equals("FileSystem", StringComparison.OrdinalIgnoreCase))
+                    {
+                        ReportOnlySupportsFileSystemPaths(path, command);
+                    }
+
+                    if (filePaths.Count > 1)
+                    {
+                        ReportMultipleFilesNotSupported(command);
+                    }
+
+                    resolvedPath = filePaths[0];
+                }
+            }
+            catch (ItemNotFoundException)
+            {
+                resolvedPath = null;
+            }
+
+            return resolvedPath;
+        }
+
+        /// <summary>
+        /// Throws terminating error for not using file system provider.
+        /// </summary>
+        /// <param name="path">The path to report.</param>
+        /// <param name="command">The command.</param>
+        internal static void ReportOnlySupportsFileSystemPaths(string path, PSCmdlet command)
+        {
+            var errorMessage = string.Format(CultureInfo.CurrentCulture, PathUtilityStrings.OnlySupportsFileSystemPaths, path);
+            var exception = new ArgumentException(errorMessage);
+            var errorRecord = new ErrorRecord(exception, "OnlySupportsFileSystemPaths", ErrorCategory.InvalidArgument, path);
+            command.ThrowTerminatingError(errorRecord);
+        }
+
+        /// <summary>
+        /// Throws terminating error for path not found.
+        /// </summary>
+        /// <param name="path">The path to report.</param>
+        /// <param name="command">The command.</param>
+        internal static void ReportPathNotFound(string path, PSCmdlet command)
+        {
+            var errorMessage = string.Format(CultureInfo.CurrentCulture, PathUtilityStrings.PathNotFound, path);
+            var exception = new ArgumentException(errorMessage);
+            var errorRecord = new ErrorRecord(exception, "PathNotFound", ErrorCategory.ObjectNotFound, path);
+            command.ThrowTerminatingError(errorRecord);
+        }
+
+        /// <summary>
+        /// Throws terminating error for multiple files being used.
+        /// </summary>
+        /// <param name="command">The command.</param>
+        internal static void ReportMultipleFilesNotSupported(PSCmdlet command)
+        {
+            var errorMessage = string.Format(CultureInfo.CurrentCulture, PathUtilityStrings.MultipleFilesNotSupported);
+            var exception = new ArgumentException(errorMessage);
+            var errorRecord = new ErrorRecord(exception, "MultipleFilesNotSupported", ErrorCategory.InvalidArgument, null);
+            command.ThrowTerminatingError(errorRecord);
+        }
+
+        /// <summary>
+        /// Gets encoding for path.
+        /// </summary>
+        /// <param name="path">The path to get file encoding.</param>
+        /// <returns>The encoding of file.</returns>
+        internal static Encoding GetPathEncoding(string path)
+        {
+            using (var reader = new StreamReader(path, Encoding.Default, detectEncodingFromByteOrderMarks: true))
+            {
+                _ = reader.Read();
+                return reader.CurrentEncoding;
+            }
+        }
+    }
+}