Why, oh why are you calling sed? Perl has very good regular expression support of its own:

open(IN, '<', $File1) or die $!;
open(OUT, '>', $Replace_html) or die $!;

while(my $line = <IN>) {
    $line =~ s/$c/$b/g;
    print OUT $line;
}

close(IN);
close(OUT);
[download]

Might be a little longer, but it doesn't rely on an external program. Plus it uses Perl's regular expressions, which are far and away better than sed in almost any way you can think of.

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated

could if possible tell me why u are using < and > when defining the files, also i ran the code u gave me , i still am not getting output in the output file , could it be coz $c and $b both have "/" in them

The version above uses the three-element form of open() (available in perl 5.6.0 and later), which is a bit safer than the two-element form. open(FH, '<', $filename) is the same as open(FH, "<$filename"). The problem is that $filename could have a '<' at the beginning, thus changing the meaning of the open(). The three-element form avoids this problem.

And yes, $c and $b need to have special regex characters escaped. (As broquaint said, variables like $c and $b have special meanings and should be avoided, but let's ignore that for the moment). If '/' is your only problem character, you can use the 'choose your own quotes' feature of Perl's regexen, such as s!$c!$b!g. In this case, the regex substitution will use '!' as a delimiter instead of '/'.

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated

quotemeta might help you with this. perldoc -f quotemeta

## warn if we get an abnormal exit status
system ("sed -e 's[$c][$b]g' $File1 > $Replace_html")
 == 0 or warn "sed had problems (exit val $?)\n";
[download]

Try this instead as escaping the slashes should do the trick

(my $search  = $c) =~ s[/](\\/)g;
(my $replace = $b) =~ s[/](\\/)g;
system("sed -e 's/$search/$replace/g' $File1 > $Replace_html")
  == 0 warn "sed had problems (exit val $?)\n";
[download]

_________
broquaint

You have to be careful when using system like you are.
What would happen if some how $File1 was "myfile ;; rm -rf ."?

looks like it didn't work , ahhhh i am gonna kill myself,