Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!tank!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.wizards
Subject: Re: Detecting Pipe Using Bourne Shell
Message-ID: <16799@mimsy.UUCP>
Date: 8 Apr 89 05:58:44 GMT
References: <18992@adm.BRL.MIL> <8385@xanth.cs.odu.edu>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 26

In article <8385@xanth.cs.odu.edu> kremer@cs.odu.edu (Lloyd Kremer) writes:
>You are trying to interpret "no arguments" as two entirely different
>directives:
>a) present menu and exit
>and
>b) read stdin instead of argument list for search targets
>
>You must devise a way of differentiating between these meanings.

Correct analysis, and a workable solution.  However:

>Many UNIX(tm) programs treat an argument of  -  as meaning 'read
>stdin instead of files'.

what is really needed here is /dev/stdin.  Alas, neither SysV (at least
SysV R 1, 2, 2.2, for 3B2, 3B5, Unix-PC, ... how many standards do we
have these days anyway? :-> ) nor BSD (at least I can count the BSD
revisions <-: ) come with a /dev/stdin.

The trend (as shown by /dev/fd/*, /proc, network file systems, and
so forth) seems to be to put everything that is visible into the file
name space ... and I think it is the right trend.  (Too bad about
S3 shm and BSD sockets.)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris