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From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: why doesn't my usage of "while(<>)" work ?
Message-ID: <10437@jpl-devvax.JPL.NASA.GOV>
Date: 17 Nov 90 00:36:49 GMT
References: <9231@pitt.UUCP>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 40

In article <9231@pitt.UUCP> al@ee.pitt.edu (Alan Martello) writes:
: what is wrong with this example ?  I want to rsh to another
: machine, process the output of the command, and then
: use "while(<>)" just like always.  
: 
: any help appreciated, please post (unless embarassing) or mail.
: I'm running perl PL 41 on a Sun-3 under SunOS 4.1
: compiled with gcc.
: 
: *******************************************************************
:        Alan R. Martello        Electrical Engineering Dept.
:         al@ee.pitt.edu           University of Pittsburgh
: *******************************************************************
: #! /bin/perl
: 
: #  get the host name for the rsh
: $host = $ENV{'HOST'};
: 
: #
: #  THESE NEXT THREE LINES ARE THE OFFENDING ONES
: #  why does this program work only when these are
: #  commented out ?
: open(WFH, "rsh $host ls |");
: while (<WFH>) {  print; }
: close(WFH);
: 
: #
: #  second while statement should copy stdin to stdout
: #
: while (<>) {
:   print;
: }
: exit;

Works fine for me.  Could you have something weird in your .cshrc that's
trying to do dialog and getting nothing from stdin?  Try

    open(WFH, "rsh $host ls </dev/null 2>&1 |");

Larry