It may be that XML::Writer is helpful. Consider:

#!/usr/lib/perl
use strict;
use warnings;
use XML::Writer;

my $out;
my $xml = XML::Writer->new(OUTPUT => \$out, DATA_MODE => 1, DATA_INDEN
+T => '   ');

$xml->xmlDecl();
$xml->startTag('doc');

while (<DATA>) {
    chomp;
    next if !length;

    my ($bibData, $quote, $primary, $sec) = /
        ^([^"]* "[^"]+"[^"]*)
        ([^\@]+)
        \@([^%]+)
        \%(.*)
        /x;

    $xml->startTag('entry');
    $xml->dataElement(bib     => $bibData);
    $xml->dataElement(quote   => $quote);
    $xml->dataElement(primary => $primary);
    $xml->dataElement(sec     => $sec);
    $xml->endTag();
}

$xml->endTag();
$xml->end();

print $out;

__DATA__
Leyson, Captain Burr.  "With or Without Gadgets."  Boys' Life.  Nov 19
+49.  p. 6.  "An old-timer knew what he had to do in a jam.  He didn't
+ need hundreds of those gadgets to guide him to safety."  @gauge %tri
+vial

"The Battle Against Baldness."  Kiplinger's Personal Finance.  Feb 194
+9.  "A little home hair-cutter gadget--a comb with a razor attached--
+ has zipped its way into fame in recent months.  Barbers pooh-pooh it
+ as a threat, but sales are going strong."  @tool %american
[download]

Prints:

<?xml version="1.0"?>

<doc>
   <entry>
      <bib>Leyson, Captain Burr.  "With or Without Gadgets."  Boys' Li
+fe.  Nov 1949.  p. 6.  </bib>
      <quote>"An old-timer knew what he had to do in a jam.  He didn't
+ need hundreds of those gadgets to guide him to safety."  </quote>
      <primary>gauge </primary>
      <sec>trivial</sec>
   </entry>
   <entry>
      <bib>"The Battle Against Baldness."  Kiplinger's Personal Financ
+e.  Feb 1949.  </bib>
      <quote>"A little home hair-cutter gadget--a comb with a razor at
+tached-- has zipped its way into fame in recent months.  Barbers pooh
+-pooh it as a threat, but sales are going strong."  </quote>
      <primary>tool </primary>
      <sec>american</sec>
   </entry>
</doc>
[download]

Excellent, this is exactly what I was looking for -- I don't even want to tell you how much time I wasted on trial and error. And to add a $year field, that searches for four-digit numbers, would that just be some kind of grep? Perhaps something like ^\d\d\d\d$ this? Or does XML::Writer not have that capability?

You don't seem to understand what GrandFather's code is doing. In particular, this chunk of code determines how the original line of text is divided into tag-able pieces:

    my ($bibData, $quote, $primary, $sec) = /
        ^([^"]* "[^"]+"[^"]*)
        ([^\@]+)
        \@([^%]+)
        \%(.*)
        /x;
[download]

That's a regex, expressed on multiple lines (thanks to the "x" modifier at the end), where the first line captures everything up through the first close-quote up to the second open-quote, and the second line captures everything from that point up to the first "@" (keyword symbol).

To get the date as a separate item, you just need to divide up the match a little differently, like this:

    my ($bibData, $date, $quote, $primary, $sec) = /
        ^([^"]* "[^"]+".*?)
        (\d{4})\.\s+
        ([^\@]+)
        \@([^%]+)
        \%(.*)
        /x;

    $xml->startTag('entry');
    $xml->dataElement(bib     => $bibData);
    $xml->dataElement(date    => $date);
    $xml->dataElement(quote   => $quote);
    $xml->dataElement(primary => $primary);
    $xml->dataElement(sec     => $sec);
    $xml->endTag();
[download]

Note how the first capture changed: it now ends with .*? to do a "non-greedy" match of any character until the next capture match is found, which is the one I added to look for 4 digits followed by a literal period and whitespace (updated to require at least one whitespace character). Then we also have to add a $date variable to the list of assignments, as well as a the $xml->dataElement() call to include the $date value in the output.

Bear in mind that if your input ever includes a line of text like this, the method above will do the wrong thing:

"Big Brother."  Review of Orwell's Novel 1984.  Nov. 2011.  "Tough sit
+uation." @tricky %unparsable.
[download]

That could be "fixed" by making the regex match more explicit -- e.g. looking for any of the 12 month abbreviations before the 4-digit year -- but then some entries might lack a month, or the month will be unabbreviated or misspelled...

Any attempt to impose structure like this on plain text has a non-zero probability of failing, because it's impossible to anticipate all the unexpected variations that eventually show up in (human-authored) plain text.

Hi Monks, I used code suggested to convert a text file into xml but getting some errors for some of the lines in the input text file. Posting those here just in case if anyone is still following and could have some suggestion on correcting it:

=====================================================

I am trying to convert a text file into xml using following code:

#!/usr/bin/perl

use strict;
use warnings;
use XML::Writer;
use XML::Simple;
use XML::LibXML;

my $out;
my $xml = XML::Writer->new(OUTPUT => \$out, DATA_MODE => 1, DATA_INDEN
+T => '   ');

$xml->xmlDecl();
$xml->startTag('doc');

my $check_1 = 0;

open(my $fh, "<", "20150625163139.txt")
    or die "Failed to open file: $!\n";
while(<$fh>) {
    chomp;
    next if !length;

    my ($string1, $string2, $subscript_name, $subscript_value) = /
        ^(.*?)::
        ([^\s]+)
        \.([^\s]+)\s+=
        \s(.*)
        /x;
    if ( $check_1 == 0 ) {
        $xml->startTag($string1);
        $check_1 += 1;
    }
    $xml->startTag($string2);
    $xml->dataElement($subscript_name => $subscript_value);
    $xml->endTag();
}

$xml->endTag();
$xml->endTag();
$xml->end();

print $out;
close $fh;
[download]

The file 20150625163139.txt contains 366 lines with format:

GI-eSTB-MIB-NPH::eSTBGeneralErrorCode.0 = INTEGER: 0
GI-eSTB-MIB-NPH::eSTBGeneralConnectedState.0 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBGeneralPlatformID.0 = INTEGER: 2076
GI-eSTB-MIB-NPH::eSTBGeneralFamilyID.0 = INTEGER: 25
GI-eSTB-MIB-NPH::eSTBGeneralModelID.0 = INTEGER: 60436
GI-eSTB-MIB-NPH::eSTBGeneralUnitAddressID.0 = STRING: 000-00802-49393-
+076
GI-eSTB-MIB-NPH::eSTBGeneralSettopMac.0 = STRING: b8:16:19:28:18:f3
GI-eSTB-MIB-NPH::eSTBGeneralRemodChan.0 = INTEGER: 3
GI-eSTB-MIB-NPH::eSTBGeneralSettopTime.0 = INTEGER: 1119302620 GPS
GI-eSTB-MIB-NPH::eSTBPurchaseStatusUnsentPurchases.0 = INTEGER: 0
GI-eSTB-MIB-NPH::eSTBPurchaseStatusUnackPurchases.0 = INTEGER: 0
GI-eSTB-MIB-NPH::eSTBPurchaseStatusLastSeqNumPurchases.0 = INTEGER: 0
GI-eSTB-MIB-NPH::eSTBPurchaseStatusLastReportBackTimePurchases.0 = INT
+EGER: 1118516578
GI-eSTB-MIB-NPH::eSTBPurchaseStatusIppvStatus.0 = INTEGER: false(2)
GI-eSTB-MIB-NPH::eSTBOobFrequency.0 = INTEGER: 75250000
GI-eSTB-MIB-NPH::eSTBOobCarrierLock.0 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBOobLostLockCount.0 = Counter32: 0
GI-eSTB-MIB-NPH::eSTBOobDataPresent.0 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBOobEMMDataPresent.0 = INTEGER: false(2)
GI-eSTB-MIB-NPH::eSTBOobSNRValue.0 = INTEGER: 24.9
GI-eSTB-MIB-NPH::eSTBOobSNRState.0 = INTEGER: good(4)
GI-eSTB-MIB-NPH::eSTBOobAGCValue.0 = INTEGER: 16
GI-eSTB-MIB-NPH::eSTBOobAGCState.0 = INTEGER: good(4)
GI-eSTB-MIB-NPH::eSTBOobNetworkPid.0 = INTEGER: 1911
GI-eSTB-MIB-NPH::eSTBOobEMMPid.0 = INTEGER: 5379
GI-eSTB-MIB-NPH::eSTBOobEMMProviderID.0 = INTEGER: 1
GI-eSTB-MIB-NPH::eSTBInBandNumberOfTuners.0 = INTEGER: 2
GI-eSTB-MIB-NPH::eSTBTunerIndex.1 = INTEGER: 1
GI-eSTB-MIB-NPH::eSTBTunerIndex.2 = INTEGER: 2
GI-eSTB-MIB-NPH::eSTBInBandTunerModulationMode.1 = INTEGER: qam256(3)
GI-eSTB-MIB-NPH::eSTBInBandTunerModulationMode.2 = INTEGER: qam256(3)
GI-eSTB-MIB-NPH::eSTBInBandTunerCarrierLock.1 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBInBandTunerCarrierLock.2 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBInBandTunerPCRLock.1 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBInBandTunerPCRLock.2 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBInBandTunerDataLock.1 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBInBandTunerDataLock.2 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBInBandTunerEMMDataPresent.1 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBInBandTunerEMMDataPresent.2 = INTEGER: true(1)
GI-eSTB-MIB-NPH::eSTBInBandTunerFrequency.1 = INTEGER: 195000000
GI-eSTB-MIB-NPH::eSTBInBandTunerFrequency.2 = INTEGER: 501000000
GI-eSTB-MIB-NPH::eSTBInBandTunerAGCValue.1 = INTEGER: 0
GI-eSTB-MIB-NPH::eSTBInBandTunerAGCValue.2 = INTEGER: 0
GI-eSTB-MIB-NPH::eSTBInBandTunerAGCState.1 = INTEGER: poor(2)
GI-eSTB-MIB-NPH::eSTBInBandTunerAGCState.2 = INTEGER: poor(2)
GI-eSTB-MIB-NPH::eSTBInBandTunerSNRValue.1 = INTEGER: 42.0
[download]

When I run the above code for this file, I get error:

Code point \u0016 is not a valid character in XML at ./<script_name>.p
+l line 34
[download]

Where line 34 is

$xml->dataElement($subscript_name => $subscript_value);
[download]

When I remove all the lines from the file 20150625163139.txt and keep only these two lines

GI-eSTB-MIB-NPH::eSTBGeneralErrorCode.0 = INTEGER: 0
GI-eSTB-MIB-NPH::eSTBGeneralConnectedState.0 = INTEGER: true(1)
[download]

The same code runs fine and generates following xml

<?xml version="1.0"?>

<doc>
<GI-eSTB-MIB-NPH>
<eSTBGeneralErrorCode>
<0>INTEGER: 0</0>
</eSTBGeneralErrorCode>
<eSTBGeneralConnectedState>
<0>INTEGER: true(1)</0>
</eSTBGeneralConnectedState>
</GI-eSTB-MIB-NPH>
</doc>
[download]

I searched for error: "Code point \u0016 is not a valid character in XML at ./Call_to_snmpwalk.pl line 32" It seems that this error is being generated due to control characters present in the text which are not allowed in xml. So I have two options:

1) Remove these control characters from the file and then print: I have tried this using

perl -pe's/\x08//g' <20150625163139.txt >20150625163139.txt
[download]

But this gives error: Bad name after g' at <script_name>.pl line 13.

2) To actually generate an xml (actual .xml file) from code and put the text that is converted in xml into this file and then read it. Do anyone have any suggestions on point 1 or 2?