dbxenv input_case_sensitive false catch FPE
The first line changes the default setting for the case sensitivity control:
dbxenv is the command used to set dbx environment variables. (For a complete list of dbx environment variables, see Setting dbx Environment Variables.)
input_case_sensitive is the dbx environment variable that controls case sensitivity.
false is the setting for input_case_sensitive.
The next line is a debugging command, catch, which adds a system signal, FPE, to the default list of signals to which dbx responds, stopping the program.