Re: error printing all text in text file

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

This more or less says "as long as you can read a line, do so and replace the contents of $show with the content of that line".

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

HTH

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Re^2: error printing all text in text file by davido (Cardinal) on Jan 11, 2022 at 16:14 UTC
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	[reply] [d/l] [select]
Re^3: error printing all text in text file by bigup401 (Pilgrim) on Jan 12, 2022 at 11:40 UTC
i appreciate thanks	[reply]
Re^2: error printing all text in text file by Marshall (Canon) on Jan 13, 2022 at 05:38 UTC
There are multiple problems with this snippet. This code will usually ~~abend with~~ throw a warning of an undefined value passed to chomp! 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]	[reply] [d/l] [select]