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From: ccdn@levels.sait.edu.au (DAVID NEWALL)
Newsgroups: comp.unix.wizards
Subject: Re: Detecting Pipe Using Bourne Shell
Message-ID: <2412@levels.sait.edu.au>
Date: 10 Apr 89 18:29:09 GMT
References: <18992@adm.BRL.MIL>
Organization: Sth Australian Inst of Technology
Lines: 19

In article <18992@adm.BRL.MIL>, ifenn%ee.surrey.ac.uk@nss.cs.ucl.ac.uk (Ian Fenn) writes:
> [ how can you tell if a program's input comes from a pipe? ]

I recommend testing to see if stdin is a terminal.  I believe the following
will do what you want:

        if [ -t 0 -a $# -eq 0 ]; then
                echo menu
                ...
        else
                ...
        fi

(I assume you only want a menu when the program is run from a terminal)

David Newall                     Phone:  +61 8 343 3160
Unix Systems Programmer          Fax:    +61 8 349 6939
Academic Computing Service       E-mail: ccdn@levels.sait.oz.au
SA Institute of Technology       Post:   The Levels, South Australia, 5095