SBT plugin for updating lines in README and other files as part of a release. Depends on the sbt-release plugin.

In project/plugins.sbt, add the plugin:

addSbtPlugin("com.github.gseitz" % "sbt-release" % "1.0.11")
addSbtPlugin("co.vitaler" % "sbt-update-lines" % "0.1.5")    // Latest release

First, define the updateLinesSchema setting, which is a Seq[UpdateLine]. The definition of an UpdateLine is:

case class UpdateLine(
  fileToModify: File,
  lineMatcher: String => Boolean,
  replacement: (String, String) => String,
  updateVcs: Boolean = true
)

The lineMatcher receives each line, and should return true for any that should be updated. Common uses are _.contains or _.matches. The replacement function receives the version being released and each line being updated, and should return a string to use as a replacement line (with no trailing line terminator). An example might look like:

updateLinesSchema := Seq(
  UpdateLine(
    file("README.md"),
    _.contains("// Latest release"),
    (v, _) => s"""libraryDependencies += "org.example" % "package" % "$v" // Latest release"""
  ),
  UpdateLine(
    file("CHANGELOG.md"),
    _.matches("## \\[Unreleased\\]"),
    (v, _) => s"## [Unreleased]\n\n## [$v] - ${java.time.LocalDate.now}"
  )
)

Finally, to actually update the lines, add the updateLines release step to your sbt-release process (anywhere after the setReleaseVersion step which defines the release version):

releaseProcess := Seq(
  // ...
  setReleaseVersion,
  updateLines,
  commitReleaseVersion,
  // ...
)

If you leave the updateVcs parameter of the UpdateLine set to true, the updated lines will be committed along with the changes to version.sbt when you call commitReleaseVersion.