I'd recommend adding an 'or die' statement to your open statement like:

open(my $fh2, ">", $output) or die "Unable to open file '$output':  $!
+\n";
[download]

Your code has a check on closing the file, but not on opening the file. Modifying your open statement to something like what I listed above will show you when the code encounters an issue with opening a file. I personally like to use the die message listed above because it will show me both the file name/path that was provided to open as well as the reason for failing to open the file.

I agree with you, but would suggest it is better not to have "\n" at the end of the die message. You get more information from $! die without it.

Update: Thanks tye: more information from die, not from $! as originally written.

Je suis Charlie.

it is better not to have "\n" at the end of the die message. You get more information from $! without it.

The extra information has nothing to do with $! (see die for details).

BTW, since you (the OP) are using Windows, you may want to include $^E in addition to $! as $^E will sometimes have a more to-the-point explanation, especially in "permission denied" scenarios.

- tye        

I'm not saying that you're wrong about that, but can you point me to where this behavior change of $! is documented?

I have never tried testing to see if die "$!" provides more information than die "$!\n". The reason that I have been including "\n" is that I'm primarily working on Windows and I have seen instances where not using "\n", the next command prompt is being displayed on the last output line of the die statement. That's not necessarily a major issue, but I do find that to be a bit annoying. By adding "\n", this puts the next command prompt on a new line.

After seeing your post, I've looked at the perldocs for open, perliol, perlopentut, and perlvar and I was not able to find anything that indicated that "\n" would affect the contents of $!. If what you are saying is true, then it might a good idea if the perldoc for open could be updated since there are a few examples of open or die structure that has "$!\n" in the input to the die statement.

On the other hand, I did find information in perlvar that corroborates what tye said about $^E potentially providing more detailed information on some operating systems (including Windows).

Considering that you are on a Microsoft platform, have you tried testing the directory you to write to and the file you are writing to (overwriting?) to ensure you have permission to write to it as your user?

  $output = $lineValue[0].".cfg";
  # begin untested code
  use File::Basename;  # May be moved to top of script
  my $output_dir = File::Basename::dirname $output;
  if ( not ( -w $output_dir ) ) {
    die "No permission to write to directory $output_dir\n";
  }
  elsif ( not ( -w $output ) ) {
    die "No permission to write to file $output\n";
  }
  # end untested code
  open(my $fh2, ">", $output) or die $!;
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Hope that helps.

http://superuser.com/questions/613313/why-cant-we-make-con-prn-null-folder-in-windows

Windows inherits from DOS.

In retrospect, I feel compelled to point out that this was not meant to be a pun, given modern day meanings for "DOS".