diff --git a/src/main/scala/gvc/Config.scala b/src/main/scala/gvc/Config.scala
index 54ad4f4..21fced1 100644
--- a/src/main/scala/gvc/Config.scala
+++ b/src/main/scala/gvc/Config.scala
@@ -28,7 +28,7 @@ case class Config(
     onlyCompile: Boolean = false,
     onlyBenchmark: Boolean = false,
     onlyErrors: Boolean = false,
-    sourceFile: Option[String] = None,
+    sourceFiles: List[String] = List.empty,
     linkedLibraries: List[String] = List.empty,
     includeDirectories: List[String] = List.empty,
     versionString: Option[String] = None,
@@ -52,15 +52,25 @@ case class Config(
         Some("Cannot combine --output and --only-verify")
       else if (exec && onlyVerify)
         Some("Cannot combine --exec and --only-verify")
-      else if (sourceFile.isEmpty && (mode == DefaultMode || mode == Describe || mode == CaseStudyMode))
+      else if (sourceFiles.isEmpty && (mode == DefaultMode || mode == Describe || mode == CaseStudyMode))
         Some("No source file specified")
-      else if (sourceFile.nonEmpty && !Files.exists(Paths.get(sourceFile.get)))
-        Some(s"Source file '${sourceFile.get}' does not exist")
+      else if (sourceFiles.nonEmpty)
+        sourceFiles.collectFirst {
+          case sourceFile if !Files.exists(Paths.get(sourceFile)) =>
+            s"Source file '${sourceFile}' does not exist"
+        }
       else if (versionString.nonEmpty && versionString.get.trim.isEmpty) {
         Some(s"Invalid version string.")
       } else None
     ).foreach(Config.error)
   }
+
+  def getSingleSourceFile(): String = {
+    if (sourceFiles.size > 1) {
+      Config.error("Cannot specify multiple input files")
+    }
+    sourceFiles.head
+  }
 }
 
 object Config {
@@ -359,14 +369,10 @@ object Config {
       case other :: _ if other.startsWith("-") =>
         error(s"Unrecognized command line argument: $other")
       case sourceFile :: tail =>
-        current.sourceFile match {
-          case Some(_) => error("Cannot specify multiple input files")
-          case None =>
-            fromCommandLineArgs(
-              tail,
-              current.copy(sourceFile = Some(sourceFile))
-            )
-        }
+        fromCommandLineArgs(
+          tail,
+          current.copy(sourceFiles = sourceFile :: current.sourceFiles)
+        )
       case Nil => current
     }
 
diff --git a/src/main/scala/gvc/benchmarking/BenchmarkExternalConfig.scala b/src/main/scala/gvc/benchmarking/BenchmarkExternalConfig.scala
index 2191c23..9c292d6 100644
--- a/src/main/scala/gvc/benchmarking/BenchmarkExternalConfig.scala
+++ b/src/main/scala/gvc/benchmarking/BenchmarkExternalConfig.scala
@@ -253,9 +253,10 @@ object BenchmarkExternalConfig {
           p.getName.endsWith(".c0")
         })
         .map(_.toPath)
-      val fileCollection = rootConfig.sourceFile match {
-        case Some(value) => c0SourceFiles ++ List(Paths.get(value))
-        case None        => c0SourceFiles
+      val fileCollection = rootConfig.sourceFiles match {
+        case List(value) => c0SourceFiles ++ List(Paths.get(value))
+        case List()      => c0SourceFiles
+        case _ => Config.error("Cannot specify multiple input files")
       }
 
       val outputDir = benchmarkRoot \ "output-dir"
diff --git a/src/main/scala/gvc/main.scala b/src/main/scala/gvc/main.scala
index 7e9248d..6b1f599 100644
--- a/src/main/scala/gvc/main.scala
+++ b/src/main/scala/gvc/main.scala
@@ -87,8 +87,8 @@ object Main extends App {
         BenchmarkMonitor.monitor(benchConfig)
       case Config.DynamicVerification | Config.FramingVerification =>
         Output.printTiming(() => {
-          val fileNames = getOutputCollection(config.sourceFile.get)
-          val inputSource = readFile(config.sourceFile.get)
+          val fileNames = getOutputCollection(config.getSingleSourceFile())
+          val inputSource = readFile(config.getSingleSourceFile())
           val onlyFraming = config.mode == Config.FramingVerification
           val ir = generateIR(inputSource, linkedLibraries)
           BaselineChecker.check(ir, onlyFraming)
@@ -159,38 +159,40 @@ object Main extends App {
           BenchmarkExternalConfig.parsePopulator(config)
         BenchmarkPopulator.populate(benchConfig, linkedLibraries)
       case Config.Describe =>
-        val inputSource = readFile(config.sourceFile.get)
+        val inputSource = readFile(config.getSingleSourceFile())
         val sourceIR = Main.generateIR(inputSource, linkedLibraries)
         val visitor = new LabelVisitor()
         val labelOutput = visitor.visit(sourceIR)
         visitor.printCounts(labelOutput.labels)
       case Config.DefaultMode =>
-        val fileNames = getOutputCollection(config.sourceFile.get)
-        val inputSource = readFile(config.sourceFile.get)
-        Output.printTiming(() => {
-          val verifiedOutput = verify(inputSource, fileNames, cmdConfig)
-          execute(verifiedOutput.c0Source, fileNames)
-        })
+        for (sourceFile <- config.sourceFiles.reverse) {
+          val fileNames = getOutputCollection(sourceFile)
+          val inputSource = readFile(sourceFile)
+          Output.printTiming(() => {
+            val verifiedOutput = verify(inputSource, fileNames, cmdConfig)
+            execute(verifiedOutput.c0Source, fileNames)
+          })
+        }
       case Config.CaseStudyMode => {
-        val fileNames = getOutputCollection(config.sourceFile.get)
-        val inputSource = readFile(config.sourceFile.get)
+        val fileNames = getOutputCollection(config.getSingleSourceFile())
+        val inputSource = readFile(config.getSingleSourceFile())
         val caseName = fileNames.baseName.split("/").last
 
         // create new dir for collected data and files
         val localTime = java.time.LocalDateTime.now()
         val outputDir = Paths.get("").toAbsolutePath.toString + "/" + caseName + "-" + localTime + "/"
-        val newSourceFile = outputDir + config.sourceFile.get.split("/").last
+        val newSourceFile = outputDir + config.getSingleSourceFile().split("/").last
         val fileNames2 = getOutputCollection(newSourceFile)
 
         val caseConfig = new Config(
                                 mode = Config.CaseStudyMode,
                                 saveFiles = true,
                                 exec = true,
-                                sourceFile = config.sourceFile,
+                                sourceFiles = config.sourceFiles,
                                 linkedLibraries = config.linkedLibraries,
                                 includeDirectories = config.includeDirectories,
                              )
-        println(Output.purple("Verifying '" + config.sourceFile.get + "' and gathering data."))
+        println(Output.purple("Verifying '" + config.getSingleSourceFile() + "' and gathering data."))
         println(Output.purple("Outputting collected data to " + outputDir))
         writeDir(outputDir)
         writeFile(newSourceFile, inputSource)
@@ -464,8 +466,6 @@ object Main extends App {
     if (cmdConfig.exec) {
       val outputCommand = Paths.get(outputExe).toAbsolutePath.toString
       sys.exit(Seq(outputCommand) !)
-    } else {
-      sys.exit(0)
     }
   }
 }