#!/usr/bin/perl -w
#use strict;
my $SCU = 'C:/Users/user/Desktop/a.txt';
open (FILE, '<', $SCU) or die "$SCU File not found : $!";
my @lines = <FILE>;
close (FILE);

my $A= '+#';
my $B= '$coin22';

my @newlines;

   push @newlines, s/$A/$B/rg for @lines;

open (FILE, '>', $SCU) or die "Could not open file $SCU: $!";
print FILE @newlines;
close (FILE);