This command enters the interactive command mode. This can be useful
in a script to interrupt the script at a certain point and allow for
interactive inspection or manual synthesis of the design at this point.
The command prompt of the interactive shell indicates the current
selection (see 'help select'):
the entire design is selected
only part of the design is selected
the entire module 'modname' is selected using 'select -module modname'
only part of current module 'modname' is selected
When in interactive shell, some errors (e.g. invalid command arguments)
do not terminate yosys but return to the command prompt.
This command is the default action if nothing else has been specified
on the command line.
Press Ctrl-D or type 'exit' to leave the interactive shell.