In build.gradle:

String portablePath(String path) {
    path
}

In subproject/build.gradle:

repoUser = "foo"
repoPassword = "bar"
repoHost = "foo.bar.com"
repoPath = "baz"

task uploadRpm {
    commandLine = ['scp', portablePath("/test"),
        "${repoUser}:${repoPassword}@${repoHost}:${repoPath}/i386/RPMS/"]
    println commandLine
}

What I get (running: 'gradle subproject:uploadRpm':

[510] gradle subproject:uploadRpm
[scp, /test, foo:bar@foo.bar.com:baz/i386/RPMS/]
:subproject:uploadRpm UP-TO-DATE

BUILD SUCCESSFUL

Total time: 1.893 secs