Updated to support file output.

project/build.properties

@@ -1 +1 @@
-sbt.version=1.9.9
+sbt.version=1.10.0

src/main/scala/gs/CalVerKeys.scala

@@ -42,4 +42,17 @@ object CalVerKeys {
     "Dump the calculated version information."
   )
 
+  /** SBT Setting that defines the filename for dumping the calculated CalVer to
+    * a file.
+    */
+  lazy val calVerOutputFile = settingKey[Option[String]](
+    "Name of the file where the calculated SemVer will be stored (if requested)."
+  )
+
+  /** Task which writes the calculated CalVer to a file.
+    */
+  lazy val calVerWriteVersionToFile = taskKey[Unit](
+    "Write the calculated CalVer to a file."
+  )
+
 }

src/main/scala/gs/CalVerPlugin.scala

@@ -1,5 +1,8 @@
 package gs
 
+import java.nio.charset.StandardCharsets
+import java.nio.file.Files
+import java.nio.file.Paths
 import sbt._
 
 object CalVerPlugin extends AutoPlugin {
@@ -9,10 +12,13 @@ object CalVerPlugin extends AutoPlugin {
 
   import autoImport._
 
+  val DefaultOutputFile: String = ".version"
+
   lazy val calVerDefaults: Seq[Setting[_]] =
     Seq(
       calVerReleasePattern    := Some(CalVer.Defaults.ReleasePattern),
-      calVerPreReleasePattern := Some(CalVer.Defaults.PreReleasePattern)
+      calVerPreReleasePattern := Some(CalVer.Defaults.PreReleasePattern),
+      calVerOutputFile        := Some(DefaultOutputFile)
     )
 
   override lazy val projectSettings: Seq[Setting[_]] = {
@@ -32,6 +38,13 @@ object CalVerPlugin extends AutoPlugin {
         val log = Keys.streams.value.log
         log.info(s"[CalVer] Version: ${calVer.value}")
         log.info(s"[CalVer] Pattern: ${calVerPattern.value}")
+      },
+      calVerWriteVersionToFile := {
+        val outputFile = calVerOutputFile.value.getOrElse(DefaultOutputFile)
+        Files.write(
+          Paths.get(outputFile),
+          calVer.value.getBytes(StandardCharsets.UTF_8)
+        )
       }
     )
   }