kotlin-stdlib / kotlin.io / java.io.File / relativeTo relativeTo fun File.relativeTo(base: File): File (source) Platform and version requirements: JVM Calculates the relative path for this file from base file. Note that the base file is treated as a directory. If this file matches the base file, then a File with empty path will be returned. Exceptions IllegalArgumentException - if this and base paths have different roots. Return File with relative path from base to this.