If it only should work for you, there's no need to use newChatHud_addLine or clientCmdChatMessage. Here's a template of what you should do.
package foobar
{
function NMH_Type::send( %this )
{
%value = %this.getValue();
if ( yourProcessingFunction( %value ) )
{
%this.setValue( "" );
}
parent::send( %this );
}
};
activatePackage( "foobar" );
function yourProcessingFunction( %msg )
{
if ( %msg $= "-myping" )
{
newChatSO.addLine( "\c6Your ping is \c3" @ serverConnection.getPing() @ "\c6." );
}
else if ( %msg $= "-disconnect" )
{
disconnect();
}
else
{
return false;
}
return true;
}