$string =~ s/\Q$substring\E/\"$substring\"/gi;
[download]

\Q..\E uses quotemeta to convert the substring into a regexp pattern that matches the substring.

There is no real need to escape the quotes :)

$string = 'a b c la la a b c la la';
$substring = 'b c';
$string =~ s/\Q$substring\E/"$substring"/gi;
print $string;
__END__
a "b c" la la a "b c" la la
[download]

Hi

Please note that in your example coding the '$sting' and '$substing' are misspelled in some occurances, to avoid this use 'use strict;'

You can escape those slashes in the matching string by using '\Q and \E' like

use strict;

my $string = "this is my sting with \ and /slashes. put substing in qu
+otes"; 
my $substring = "with \ and /slashes"; 
$string =~ s/\Q$substring\E/\"$substring\"/gi; 

print $string;
[download]

Punitha

Thanks for quick reply. This way it has deleted "\" from substring. On printing $string i am getting >>this is my sting "with and /slashes". put substing in quotes But i want it this way >>this is my sting "with \ and /slashes". put substing in quote

No, $string and $substring don't contains any "\" to begin with.

# The string these literals produce don't contains any "\".
my $string = "my string with \ and / slashes."; 
my $substring = "with \ and / slashes"; 
print("$string\n");
print("$substring\n");
print("\n");

# This is what the literals should be.
$string = "my string with \\ and / slashes."; 
$substring = "with \\ and / slashes"; 
print("$string\n");
print("$substring\n");
print("\n");

# It works.
$string =~ s/\Q$substring\E/\"$substring\"/gi;
print("$string\n");
[download]

my string with  and / slashes.
with  and / slashes

my string with \ and / slashes.
with \ and / slashes

my string "with \ and / slashes".
[download]

Hi

Check the input itself is not containing the '\', because it is interpolated in double quotes.

use strict;

my $string = "this is my sting with \ and /slashes. put substing in qu
+otes"; 
my $substring = "with \ and /slashes"; 
print $string;

$string =~ s/\Q$substring\E/\"$substring\"/gi;

OUTPUT:
this is my sting with  and /slashes. put substing in quotes
[download]

Instead use single quote in the input like,

use strict;

my $string = 'this is my sting with \ and /slashes. put substing in qu
+otes'; 
my $substring = 'with \ and /slashes'; 
print $string;

$string =~ s/\Q$substring\E/\"$substring\"/gi;

OUTPUT:
this is my sting with \ and /slashes. put substing in quotes
[download]

This will give the correct output

Punitha