kotlin-stdlib / kotlin.io / java.io.File / useLines useLines JVM 1.0 inline fun <T> File.useLines( charset: Charset = Charsets.UTF_8, block: (Sequence<String>) -> T): T(source) Calls the block callback giving it a sequence of all the lines in this file and closes the reader once the processing is complete. Parameters charset - character set to use. By default uses UTF-8 charset. Return the value returned by block.