import hudson.util.RemotingDiagnostics;

print_ip = 'println InetAddress.localHost.hostAddress';
print_hostname = 'println InetAddress.localHost.canonicalHostName';

// here it is - the shell command, uname as example 
uname = 'def proc = "uname -a".execute(); proc.waitFor(); println proc.in.text';

for (slave in hudson.model.Hudson.instance.slaves) {
    println slave.name;
    println RemotingDiagnostics.executeGroovy(print_ip, slave.getChannel());
    println RemotingDiagnostics.executeGroovy(print_hostname, slave.getChannel());
    println RemotingDiagnostics.executeGroovy(uname, slave.getChannel());
}