Hi Vladimir, I'm a bit confused. Why does the following short option name not work: #include <boost\program_options.hpp> using namespace std; using namespace boost; namespace po = boost::program_options; int main( int argc, char* argv[] ) { string input; po::options_description settings( "" ); settings.add_options() ( "input_1,I1" , po::value< string >( &input ) ->default_value( "" ) , "" ); po::options_description options; options.add( settings ); po::variables_map variables; store( parse_command_line( argc , argv , settings ) , variables ); notify( variables ); cout << input << endl; return 0; } -I1"hello" wont work? In my project I have two input files. The long names are input_1 and input_2. It seems to me I cannot have numbers in the short version like: -I1"hello" -I2"world". Any ideas? Christian