while(chomp(my $line = <$fh>)) {
    $show = "$line\n";
}
[download]

1. What do you think, will be in $show after reading the second, third, etc. line?
2. Look at perldoc perlop under "Additive Operators" and then under Assignment Operators

It's likely that snippet should be:

while(chomp(my $line = <$fh>)) {
    $show .= "$line\n";
}
[download]

And that is pretty much functionally equivalent to:

{
    local $/ = undef;
    $show = <$fh>;
}
[download]

...except that his code would append a newline at the end of the file if one wasn't there already. So $show =~ s/(?<!\n)\z/\n/ if that trailing newline is important. If he intended to keep the lines separated then he could slurp into an array.




Dave

i appreciate thanks

There are multiple problems with this snippet.

1. This code will usually abend with throw a warning of an undefined value passed to chomp!
2. The last line of the file can be missed if its not terminated by \n.
What while (chomp (my $line = <$fh>)){} means is execute the while code if chomp is successful in removing at least 1 character from $line.

Assuming that the last line is terminated properly, after all data is read from the filehandle, $line will be undefined. chomp won't like that and will barf.

Now if the last line of the file is not terminated, an even more insidious thing can happen. That last line will be ignored because chomp does not remove any characters from that line.

So, don't use this construct.
here is proof:

use strict;
use warnings;
$|=1;

my $data = <<END;
asdf fjfjf
324
0
2345
2wefrwef
END

#chomp $data; #toggle on/off to see results

open my $fh, "<", \$data or die "$!";

while (chomp (my $line = <$fh>))
{
    print $line;
}

__END__
asdf fjfjf324023452wefrwefUse of uninitialized value $line in chomp at
+ testchompWhile.pl line 15, <$fh> line 5.
asdf fjfjf32402345
[download]

am not getting all lines

Concatenate or use an array.

i would like to have lines outputted in colors like blue and red

Use CSS.