If FA is started with a single command-line argument, it runs in batch mode. The argument specifies the input and output file names. For instance, if FA is started as
fa demoFA looks for an input file named demo.in, writes to an output file demo.out or a plot file demo.plot.
If FA is invoked without command-line argument it reads standard input and writes to standard output. With input redirection it will still run in batch mode, as in
fa < demo.in > demo.out