endsWith

Determines whether this file path ends with the path of other file.

fun File.endsWith(other: File): Boolean(source)

import java.io.File

fun main() {
    val parentDir = File("/home/user/documents")
    val file1 = File("/home/user/documents/report.pdf")
    val file2 = File("/home/user/music/song.mp3")

    println(file1.endsWith(parentDir)) // true
    println(file2.endsWith(parentDir)) // false
}

Source