# make a global array for storage
my @array;

#or make a global scalar string 
my $storage_string;

.....
.....

    while(!$channel->eof())
    {
        my $buff;
        $channel->read($buff, 1024);
       
        # print $buff;
         push @array, $buf;   # pushes $buf into next array slot
       # or use a concated string
        $storage_string .= $buf;   # concantates $buf onto end of string
    }