SYMPHONY's command-line switches are all lower case letters. The user can use any upper case letter (except 'H' and as specified below) for command line switches to control user-defined parameter settings without the use of a parameter file. The function user_usage() can optionally print out usage information for the user-defined command line switches. The command line switch -H automatically calls the user's usage subroutine. The switch -h prints SYMPHONY's own usage information. In its default configuration, the command-line switch -F is used to specify the file in which the instance data is contained (either an MPS file or an GMPL/AMPL file). The -D switch is used to specify the data file if an GMPL/AMPL file is being read in (see the README file).