use strict;
my $str = ' USA - Boston "sa-boston-ubuntu-l2tp.xvnet.net"
USA - Los Angeles "a1-ubuntu-l2tp.expressprovider.com"
USA - Atlanta "tlanta-ubuntu-l2tp.xvnet.net"
Canada - Montreal "ontreal1-ubuntu-l2tp.xvnet.net
"';
my $regex = qr/\n.*\"/mp;
my $subst = '\\"';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html