Program.cs

@@ -0,0 +1,80 @@
+public class Program
+{
+
+    public static void Main()
+    {
+        var path = @"C:\Users\tlamb\Downloads\AccessGUDID_Delimited_Full_Release_20231001";
+        var input = "gmdnTerms.txt";
+        var format = "gmdnTerms-{0:000}.txt";
+        //var input = "device.txt";
+        //var format = "device-{0:000}.txt";
+        var size = int.MaxValue;
+        var info = new FileInfo(Path.Combine(path, input));
+        size = (int)Math.Min(info.Length / 10, size);
+        Split(Path.Combine(path, input), Path.Combine(path, format), size);
+    }
+
+    public static void Split(string inputfile, string outputfilesformat, int maxSize = int.MaxValue, bool hasHeader = true)
+    {
+        int i = 0;
+        int size = 0;
+        StreamWriter outfile = null;
+        bool firstFile = true;
+        string headerLine = null;
+        string line;
+
+        try
+        {
+            using (var infile = new StreamReader(inputfile))
+            {
+                while (!infile.EndOfStream)
+                {
+                    line = infile.ReadLine();
+                    if (hasHeader && headerLine == null)
+                    {
+                        headerLine = line;
+                    }
+                    if (size > maxSize)
+                    {
+                        if (outfile != null)
+                        {
+                            outfile.Dispose();
+                            outfile = null;
+                            size = 0;
+                        }
+                    }
+                    if (string.IsNullOrEmpty(line))
+                    {
+                        if (outfile != null)
+                        {
+                            outfile.Dispose();
+                            outfile = null;
+                            size = 0;
+                        }
+                        continue;
+                    }
+                    if (outfile == null)
+                    {
+                        outfile = new StreamWriter(
+                            string.Format(outputfilesformat, i++),
+                            false,
+                            infile.CurrentEncoding);
+                        if (!firstFile && hasHeader)
+                        {
+                            outfile.WriteLine(headerLine);
+                        }
+                        firstFile = false;
+                    }
+                    outfile.WriteLine(line);
+                    size += line.Length;
+                }
+
+            }
+        }
+        finally
+        {
+            if (outfile != null)
+                outfile.Dispose();
+        }
+    }
+}

splitfile.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

splitfile.sln

@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.5.33516.290
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "splitfile", "splitfile.csproj", "{3687F04B-882A-4524-BAD7-1E7D68B3661C}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{3687F04B-882A-4524-BAD7-1E7D68B3661C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3687F04B-882A-4524-BAD7-1E7D68B3661C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3687F04B-882A-4524-BAD7-1E7D68B3661C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3687F04B-882A-4524-BAD7-1E7D68B3661C}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {C6388701-C197-4C93-8B96-20A593AEF339}
+	EndGlobalSection
+EndGlobal