Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!rbj
From: rbj@uunet.uu.net (Root Boy Jim)
Newsgroups: comp.lang.perl
Subject: Re: better head
Message-ID: <1991May16.205446.15295@uunet.uu.net>
Date: 16 May 91 20:54:46 GMT
References: <1991May16.152356.3186@convex.com>
Organization: UUNET Communications Services, Falls Church, VA
Lines: 44

tchrist@convex.COM (Tom Christiansen) writes:
>Here's a little head clone I once wrote out of frustration 
>with head's misbehaving on files with long lines.  

Piping to "head -#" is the same as piping to "sed #q".
Sed probably has problems with long lines too, tho.

>    #!/usr/bin/perl
>    #
>    # head -- perl clone of head command, but without heads silly 
>    #	  limits regarding line lengths.  runs faster than 
>    #	  C version, too!   tchrist@convex.com
>
>    $num = ($ARGV[0] =~ /^-(.+)/ && shift) ? $1 : 10; 
>    die "$0: badly formed number: $1\n" unless $num =~ /^\d+$/;
>
>    unshift(@ARGV, '-') unless $argc = @ARGV;  # <> changes @ARGV
>    while (<>) {
>	if ($. == 1 && $argc > 1) {
>	    print "\n" if $deja_imprime++;

It's deja vu all over again :-)

>	    print "=> $ARGV <=\n" ;
>	}

So far, so good.

>	if ($. <= $num) {
>	    print;
>	} else {
>	    close ARGV;
>	} 

I think you're reading too many lines.
Wouldn't "print; close ARGV if $. == $num" be better?

>    } 

I think you missed something tho.
What happens if some of the files have less than $num lines?
-- 
		[rbj@uunet 1] stty sane
		unknown mode: sane