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From: barmar@think.com (Barry Margolin)
Newsgroups: comp.unix.wizards
Subject: Re: Why is 'more' giving the 'next file' prompt?
Message-ID: <36072@think.Think.COM>
Date: 3 May 90 22:29:54 GMT
References: <1990May3.160744.25250@bath.ac.uk>
Sender: news@Think.COM
Reply-To: barmar@nugodot.think.com (Barry Margolin)
Organization: Thinking Machines Corporation, Cambridge MA, USA
Lines: 44

In article <1990May3.160744.25250@bath.ac.uk> exspes@bath.ac.uk (P E Smee) writes:
>Ok, folks, here's one which my boss asked for an answer to the other
>day, and I don't see the answer.  The context is (4 different variants
>of) 4.3BSD  (on 4 different platforms).  Make yourself a small text
>file, say 'fred'.  Then try the command line:
>
>   cat fred | csh -c 'cat >tempxxx ; more tempxxx'
>
>Before 'more' puts anything out, it gives the 'Next file (tempxxx):'
>prompt.  Why does it think tempxxx is the second file?  What's the
>first?

'more' is noticing that its standard input isn't a terminal, so it's first
displaying the standard input.  Here's a way to see this more clearly:
create two text files, 'foo' and 'bar', and then do:

	more foo < bar

First it will show you the contents of 'bar', and the second file will be
'foo'.

You can fix your problem by making 'more's standard input a terminal, e.g.

	cat fred | ( cat >tempxxx ; more tempxxx </dev/tty )

>  The purpose of
>piping through 'cat' into a temp file and then giving that to 'more' as
>an arg is that in that case 'more' will allow you to move backwards;
>while if 'more' is processing stdin you can only go frontwards.

Get 'less'.  It allows going backward in any stream.

>  In the
>context of the original, the shell invocation is needed in order to
>allow the (second) 'cat' and the 'more' to be joined with ';' rather
>than being '|'ed together.

You can also use parentheses, as in my example.

--
Barry Margolin, Thinking Machines Corp.

barmar@think.com
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