Remember to close the file handle after writing.

Perl closes the file handle for you automatically at program exit, but if you try to re-read the file from the same process, or maybe kill your program, that might not happen, or too late.

It works for me (perl 5.14.3, Fedora 17 Linux.) The script should die if there is a permission problem preventing you from creating or writing to the file, so... have you double checked that it actually reaches the open and print statements in your second snippet?

It's often difficult to debug a script when only sections of it are posted; the bug is often a subtle interaction between the parts of the script that you are already suspicious of and the ones that are already known to be "correct."

Yes, the code is reaching that point. When i am debugging the code it is giving me output like below

C:\>perl -d 9.pl

Loading DB routines from perl5db.pl version 1.3
Editor support available.

Enter h or `h h' for help, or `perldoc perldebug' for more help.

main::(9.pl:11):        my %myhash1 = ();

  DB<1> n
main::(9.pl:12):        my %myhash2 = ();

  DB<1>
main::(9.pl:13):        my $key;

  DB<1>
main::(9.pl:14):        my $val;

  DB<1>
main::(9.pl:16):        my $xml = new XML::Simple;

  DB<1>
main::(9.pl:18):        my $data1 = $xml->XMLin("sample.xml");

  DB<1>
main::(9.pl:20):        my $data2 = $xml->XMLin("sample2.xml");

  DB<1>
main::(9.pl:25):        open FH5, ">>tagfile1" or die "error in readin
+g..debug 1
";

  DB<1>
main::(9.pl:29):        print FH5 Dumper($data1) or die $!;

  DB<1>
main::(9.pl:32):        while (<FH5>)
main::(9.pl:33):        {

  DB<1>
main::(9.pl:43):        close FH5;
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I am using perl v5.10.0 on windows.

Oh. The file is being written to, but you can't read it because it was opened for append but not read (mode ">>" instead of "+>>"), and also because, due again to the append access, it is already positioned to the end of file when you do the first read.

If you change the open mode from ">>" to "+>>", and insert   seek FH5, 0, 0 or die "Seek failed, $!"; just before  while (<FH5>) it should work.

Another way would be to close FH5 and then reopen it for input (mode "<") just before trying to read it.

It worked for me also (Perl v5.16.2). It would be helpful if you could post some of the surrounding code.

Lexical variables are preferred to bareword filehandles.

open my $fh5, ">>", "tagfile1" or die "Error: $!\n";
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You may want to take a look at perldebtut and use the debugger to make sure your code is actually reaching the open / print statements as suggested by quester.

And as always,

use strict;
use warnings;
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Thanks , it worked after I changed my file handler from bareword to my $FH5