Gradle: Check current OS

build.gradle

ant.condition(property: "os", value: "windows") { os(family: "windows") }
ant.condition(property: "os", value: "unix"   ) { os(family: "unix")    }

task typeos << {
    switch(ant.properties.os){
        case 'windows':
            println 'This is windows.'
            break
        case 'unix':
            println 'This is unix.'
            break
    }
}