• Read Applying Unix Interface-Design Patterns from TAOUP
• Read Silence Is Golden from TAOUP

• Connect to your shell account via PuTTY or ssh and read source of bc at /usr/src/bc-1.06/bc/main.c

  for syntax highlighting and easy line number open in vim, or run

  $ source-highlight -f esc256 -s c </usr/src/bc-1.06/bc/main.c | less -NR

Self Study

1. Does our wordfreq program follow the Polyvalent-Program Pattern?

2. Has our wordfreq program followed the “Silence is Golden” rule? Why or why not?

3. Identify the functions defined in main.c of the bc source. At a high level, what does each one do?

4. At what line of bc’s main.c do each of the following modules start:

   • command line option parsing
   • the read/parse/execute interpreter loop (the loop itself is actually hidden away in a function, what is the name of this top-level function called in main()?)

5. Where in the source of bc is the check to determine interactive mode vs. non-interactive mode? What function is used? Read the man page for this function.