I am maintaining a script that does this: 
sub setLineBreak {
    my $inFile = shift;
    $/ = "\n";
    open( IN, "<$inFile" ) or die "Cannot open $inFile: $!\n";
    while (<IN>) {
        if ( $_ =~ /\r\n/ ) {
            print "DOS line breaks detected ...\n" if ($verbose);
            $/ = "\r\n";
            last;
        }
        elsif ( $_ =~ /\r/ ) {
            print "Mac line breaks detected ...\n" if ($verbose);
            $/ = "\r";
            last;
        }
        else {
            print "Unix line breaks detected ...\n" if ($verbose);
            $/ = "\n";
            last;
        }
    }
    close IN;
}

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The idea is that the input line separator needs to be detected and $/ is then adjusted accordingly. If all you do, subsequently, is open the file, and do: 
while(<FILE>){
  chomp;
  # etc.
}

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then I don't think that while $/ adjustment thing is necessary. I for one have never seen such a check before. I'm tempted to just remove the whole sub. Why shouldn't I? Thanks!

In reply to alter $/ - but why? by rvosa

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