How to get strings inbetween two Strings - bash

Question

I have group of html files where i have to extract content between <hr> and </hr> tags.I have done everything except this extraction.What i have done is
1.Loaded all html files and store it in #html_files.
2.Then I am storing each file's content in #useful_files array.
3.Then I am looping the #useful_files array and checking each line where <hr> is found.If found I need next lines of content in #elements array.
Is it possible.Am I in the right?
foreach(#html_files){
$single_file = $_;
$elemets = ();
open $fh, '<', $dir.'/'.$single_file or die "Could not open '$single_file' $!\n";
#useful_files = ();
#useful_files = <$fh>;
foreach(#useful_files){
$line = $_;
chomp($line);
if($line =~ /<hr>/){
#elements = $line;
}
}
create(#elements,$single_file)
}
Thanks !!!
My input html file will be like this
<HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
<P STYLE="margin-top:0px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">Lorem ipsum dolor sit amet, consectetur adipiscing elit. </FONT></P>
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px"> </P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE">
<TR>
<TD WIDTH="45%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="4%"></TD>
<TD VALIGN="bottom"></TD>
<TD WIDTH="4%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="44%"></TD></TR>
<TR>
<TD VALIGN="top"></TD>
<TD VALIGN="bottom"><FONT SIZE="1"> </FONT></TD>
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom"><FONT SIZE="1"> </FONT></TD>
<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2">Title:</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1"> </FONT></TD>
<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2">John</FONT></TD></TR>
</TABLE>
<p Style='page-break-before:always'>
<HR SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">
The html code which i have copied here is just the sample.I need the exact content between the <hr> in the #elementsarray.

Answer 1

In a simplest way you may do this:
my #cont;
foreach (#ARGV) {
open my $fh,'<',$_;
push #cont,join('',map { chomp; $_ } <$fh>)=~m%<hr>(.*?)</hr>%g;
}
#print join("\n",#cont,'');
And yes, dont worry: all files will be closed on exit "automagically" :)
Hint: uncomment print statement to see the result.

Answer 2

You can use grep in the command line:
grep -Pzo '<hr>\K((.|\n)*)(?=</hr>)' file.html
This will allow you to extract anything between <hr> and </hr> even if new lines are present.
Example:
tiago#dell:/tmp$ grep -Pzo '<hr>\K((.|\n)*)(?=</hr>)' <<< '<hr>a b c d </hr>'
a b c d
tiago#dell:/tmp$ grep -Pzo '<hr>\K((.|\n)*)(?=</hr>)' <<< $'<hr>a b\nc d </hr>'
a b
c d
And of course you can run grep against multiple files.

Answer 3

I know people say not to parse HTML with a regex, but this seems like the kind of relatively simple task that warrants the use of a regex.
Try this:
if ($line =~ m/<hr>(.*?)<\/hr>/){
push #elements, $1;
}
This will extract the text between <hr> and </hr> and store it in the next index in the #elements array.
Also you should ALWAYS use strict; and use warnings; at the top of your code! This will stop you from making dumb mistakes and prevent many needless headaches down the road.
You should also close your file after you are done extracting its contents into the #useful_files array! close $fh;
(On a side note, the name of this array is misleading. I would suggest you name it something like #lines or #file_contents since it contains the contents of a single file... not multiple files as your variable name seems to suggest.)