Shell Programming and Scripting

This is nice
This  Got it

local $/;
open FH,"<a.txt";
my $str=<FH>;
$str=~s/'[^']*'//mg;
print $str;

1. Since you want to delete lines between single quotes, In sed you can write commands in text file like.

$cat t.sed
/./!d
:loop
$!{
N
/\n$/!b loop

}
s/'[^']*'//g

Input File:
$ cat input
This is nice 'boy'
This 'is
bad
boy.' Got it

Execute it:
$ sed -f t.sed input
This is nice
This  Got it

$ awk -v RS="\047" '!(NR%2){gsub(/\n/, " ");print}' file
boy
is bad boy.

awk -v RS="\047" '(NR%2){gsub(/\n/, " ");gsub(/^ /, "");print}' file
This is nice 
This 
Got it