With Awk and Grep i need to print some lines - bash

Question

I am fresher in writing perl scripts,so i am asking this as question or support on this, below is the code
start pattern1
line1
Matching pattern can be here
line2
Matching Pattern can be here
line3
line4
...
end pattern1
.
start pattern1
line1
line2
start pattern1
start pattern1
line1
Matching pattern can be here
line2
start pattern1
so from perl i need to grep the lines between start pattern1 ... end pattern1,
for this i am using awk command to grep
$cmd = q(awk '/start pattern1/,end pattern1 /' x.file );
$n1 = system($cmd);
For this output works fine,Below is the output,
start pattern1
line1
**Matching pattern can be here**
line2
**Matching Pattern can be here**
...
end pattern1
But in the files i have 1000 of lines like this, so i need to grep those lines which have Matching pattern. i.e i need to grep only those starting pattern lines to ending pattern lines has matching pattern
For this i tried
$cmd = q(awk '/start pattern1/,end pattern1 /' x.file | grep '$n2\|line4');
$n1 = system($cmd);
But when i use the above command i don't see any output
Here $n2 contains some pattern which is grepped from another file.
if i use direct matched patternin place of $n2 it works fine, why cant i use $n2 here?
Note:i am using this in perl script
From the Awk command i get all the lines between start pattern1...end pattern1,But i have 1000 of such prints, so i need the bunch of the lines of start pattern1 to end pattern1 of thos which get matched with the matching pattern
The expected output when i do is,
start pattern1
line1
Matching pattern can be here
line2
Matching Pattern can be here
line3
line4
...
end pattern1
start pattern1
line1
Matching pattern can be here
line2
start pattern1

Answer 1

No need to summon awk from within perl since perl is much more powerful than awk.
It's not clear to me whether you want every line between start pattern1 and end pattern1 if there is at least one match inside, or just the matching lines.
If every line between start and end if match:
my #blocks = join("",<>)=~/start pattern1\s*(.*?)end pattern1/gsi;
print grep /matching pattern/i, #blocks;
If every line INCLUDING start|end pattern1:
my #blocks = join("",<>)=~/(start pattern1.*?end pattern1\s*)/gsi;
If just lines with /matching pattern/ between start and end:
print grep { /start pattern1/i../end pattern1/i and /matching pattern/i } <>;
Put that inside a file program.pl and run:
perl program.pl inputfile > outputfile
Some explanation might be needed: join("",<>) returns the whole inputfile as one multi-line string. The /gsi modifiers means: g matches globally so that the #block array will contain what is matched by the parentheses, one array element for each match (without g the #block array would just get the first block of lines), s means that . also matches newline characters which it otherwise wouldn't and i matches by ignoring case (sees no difference between a-z and A-Z letters). The question mark in .*? means no-greedy matching of every character, that is, match until the next end pattern1 and not the last. The <> returns the lines of inputfile (args after perl program.pl) as an array of strings. The .. is the flip-flop operator which is true after the left side becomes true and false after the right side becomes true and stays false until the left side is true again and so on.