<refactor>

src/Rbom/Main.cs

@@ -0,0 +1,46 @@
+namespace Dot.Rbom;
+
+[Description(nameof(Str.TrimUtf8Bom))]
+[Localization(typeof(Str))]
+public sealed class Main : FilesTool<Option>
+{
+    private readonly byte[] _utf8Bom = { 0xef, 0xbb, 0xbf };
+
+
+    private bool CloneFileWithoutBom(Stream fsr, ref string tempFile)
+    {
+        Span<byte> buffer  = stackalloc byte[_utf8Bom.Length];
+        var        readLen = fsr.Read(buffer);
+        if (readLen != _utf8Bom.Length || !buffer.SequenceEqual(_utf8Bom)) return false;
+
+        using var fsw = CreateTempFile(out tempFile);
+        int       data;
+        while ((data = fsr.ReadByte()) != -1) fsw.WriteByte((byte)data);
+        return true;
+    }
+
+
+    protected override async ValueTask FileHandle(string file, CancellationToken _)
+    {
+        ShowMessage(1, 0, 0);
+
+        string tmpFile = default;
+        await using (var fsr = OpenFileStream(file, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) {
+            if (fsr is null) {
+                ShowMessage(0, 0, 1);
+                return;
+            }
+
+            if (CloneFileWithoutBom(fsr, ref tmpFile)) {
+                if (Opt.WriteMode) File.Copy(tmpFile, file, true);
+                ShowMessage(0, 1, 0);
+                UpdateStats(Path.GetExtension(file));
+            }
+            else {
+                ShowMessage(0, 0, 1);
+            }
+        }
+
+        if (tmpFile != default) File.Delete(tmpFile);
+    }
+}

src/Rbom/Option.cs

@@ -0,0 +1,3 @@
+namespace Dot.Rbom;
+
+public class Option : DirOption { }