todo

早期freebsd实现

1. Rethink protection glitches on REMOTE & PHONES
   files (setuid/setgid??).

2. Make clean fix for scripting being set in .tiprc

3.  change EOFREAD to recognize more general strings.

4.  add an option that returns an exit status based on
    whether resources for the requested operation are available.

5.  write a program to list known systems (a quick shell script
    should do it); people keep forgetting the names.

6.  change remote file descriptions so that acu attributes are
    are attached to a device so that several different devices
    can be used to get to the same system (perhaps hardwired
    and phone line).  got any ideas here?  I'm looking at something
    like dv=cua1,cul1,dn11;cua2,,df03.