This command enables you to derive new user-defined commands
from existing commands. User-defined commands accept arguments separated
by whitespace. You can use the arguments in expressions by using
print 4+$arg0 # add 4 to the first argument and print result
Specifies the command name followed by one or more debugger commands.
Enter each debugger command on a new line and terminate the
definecommand by using the
Existing built in commands cannot be redefined.