How to read from specific line to another line - Perl - regex

Question

I'm doing a Perl script and I have a log file where I need to extract data from. I want to know how to read from a specific line to another line(not end of file).
I tried it this way by putting a last if if it reaches the line that I want to stop at but it doesn't work. The line that I want to start reading from is <TEST_HEAD TH 1> and stops at </TEST_HEAD TH 1>. I'm doing this because my regular expression captures data that I do not need, so I tried to read from a specific line to another line.
This is what I've done so far:
while(<$log_fh>)
{
if($. =~ /\<TEST_HEAD TH 1\>/)
{
if ( /Computer Name:\s*(\S+)(-\d+)/i )
{
$details{tester_name} = $1 . $2;
$details{tester_type} = $1;
push #{$details{tester_arr}}, $1 . $2;
}
elsif ( /Operating System:\s*(.*\S)/i )
{
$details{op_sys} = $1;
}
elsif ( /IG-XL Version:\s*([^;]*)/i )
{
$details{igxl_vn} = $1;
}
elsif ( /^([\d]+)\.\d\s+(\S+)\s+([\d-]*)\s+([\d|\w]*)(?=\s)/ )
{
push #{$details{slot}}, $1;
push #{$details{board_name}}, $2;
push #{$details{part_no}}, $3;
push #{$details{serial_no}}, $4;
}
last if $. == /\<\/TEST_HEAD TH 1\>/;
}
}
Just a modified sample of the raw data file:
<TEST_HEAD TH 1> #Start reading here
(Lines containing data to be captured)
</TEST_HEAD TH 1> #end reading here

Answer 1

Without going much into the nested matching logic you may want to change
if($. =~ /\<TEST_HEAD TH 1\>/)
into
if (/<TEST_HEAD TH 1>/ .. /<\/TEST_HEAD TH 1>/)
What you ask is actually XY problem and it would be better to process xml like document with xml parser. Parsing complex XML in Perl

Answer 2

Without knowing specifically how your data looks, I'd also offer another approach.
Set $/ to a record separator, and then you grab a chunk of text in one go. You can then apply a bunch of different regexes to it all at once.
E.g.:
local $/ = 'TEST_HEAD';
while (<$log_fh>) {
next unless m/^\s*TH/;
my ( $tester_name, $tester_id ) = (m/Computer Name:\s*(\S+)(-\d+)/i);
my ($op_sys) = (m/Operating System:\s*(.*\S)/i);
my ( $slot, $board, $part, $serial ) =
(m/^([\d]+)\.\d\s+(\S+)\s+([\d-]*)\s+([\d|\w]*)(?=\s)/m);
# etc.
# then validate and update your array:
$details{$tester_name} = $tester_name;
## etc.
}