bang problems in vi

[adam.v.reed]

In article <756 at gnosys.svle.ma.us>, gst at gnosys.svle.ma.us (Gary S. Trujillo) writes:
> In article <1990Jul20.032240.29834 at cbnewsj.att.com>
> 	avr at cbnewsj.att.com (adam.v.reed) writes
> 
> (in connection with running interactive stuff only when standard input
>  is coming from a tty):
> 
> > case $- in *s* | *i* )
> > 	# your interactive stuff, stty etc., goes here
> > ;;
> > esac
> > 
> > 				Adam_V_Reed at ATT.com
> 
> Can you explain what's going on here?  Looks as if the arg string sent
> to the forked ksh contains a "s" or an "i" if the shell is interactive.
> Why is that?

RTFM. "$-" contains the current flags, not the arg string.
And if the shell is interactive, the s flag or the i flag (or both)
must be set.

> My solution comes from something posted a couple of years ago.
> In your .profile, stick the lines:
> 	START=~/.kshrc
> 	ENV='${START[(_$-=1)+(_=0)-(_$-!=_${-%%*i*})]}'
> Then you put commands in your .kshrc that you want to have executed
> iff the shell is running interactively.  (Please don't ask me what
> the "ENV=..." command means, but I can dig it up from the original
> message if enough folks really want to know.  I think the idea is
> that the ENV environment variable, which tells ksh where to read
> commands from when it starts up, either gets set to ~/.kshrc or to
> the null string, depending on some stuff that determines whether
> the shell is running interactively or not.)

Apart from being illegible, your "solution" is weak: if any
of your aliases define useful filters, you may wish to use them from
within vi. I can do that. Can you?
					Adam_V_Reed at ATT.com