replaceIndent

Detects a common minimal indent like it does trimIndent and replaces it with the specified newIndent.

fun String.replaceIndent(newIndent: String = ""): String(source)

val text = """
    |    first line
    |    second line
    |    third line
""".trimMargin()

val result = text.replaceIndent("  ")  // replace minimal indent with two spaces

println(result)

Source