my $string = "{'totalResultsCount':71-24,'securityList':[{'cusip':'91%279-6.H:Y8','issueDate':'2016-06-02T00:00:00','securityType':'Bill'}";

$string =~ /'cusip':'([\w\-\$\.\%\:]+)'/;

if ( defined $1 ) {
    $string = $1;
    print "first is : $string \n" for $string =~ s/\W//g;;
	} 
	else {
	print " first is not defined\n";
}

##</code><code>##

C:\Users\james\Desktop\perlmonks>pm.pl
first is : 912796HY8

##</code><code>##

my $string = "{'totalResultsCount':71-24,'securityList':[{'cusip':'91%279-6.H:Y8','issueDate':'2016-06-02T00:00:00','securityType':'Bill'}";
$string =~ s/.*('cusip':'([\w\-\$\.\%\:]+)').*/$2/g;
print "first is : $string \n" for $string =~ s/\W+//g;

##</code><code>##

C:\Users\james\Desktop\perlmonks>pm.pl
first is : 912796HY8