Consider your code with some indentation added

#!/usr/bin/perl -w

use strict ;
use diagnostics;
use LWP::Simple ;

print "This will get the time from an NIST clock 5 times
and then ask you if you want to continue.  Use 'y'
to continue and any other key to stop:\n\n" ;

my $answer ;
my $quit = 0 ;

until ($quit) {
     getprint("http://132.163.4.101:13") ;
     getprint("http://132.163.4.101:13") ;
     getprint("http://132.163.4.101:13") ;
     getprint("http://132.163.4.101:13") ;
     getprint("http://132.163.4.101:13") ;
     print "Do you  want to continue?  " ;
     $answer = <STDIN> ;
     chomp $answer ;
} 
if ($answer ne 'y') {     
    print "OK\n" ;
} else { 
    $quit = 1 ;
    die "OK!\n\n" ;
}
print "Good-bye!\n\n" ;
[download]

I have indented your code as I normally would. The problem as you can see is that you test the conditional outside the until loop. No test == No exit. You could also simplify a lot to this:

#!/usr/bin/perl -w

use strict ;
use diagnostics;
use LWP::Simple ;

print "This will get the time from an NIST clock 5 times
and then ask you if you want to continue.  Use 'y'
to continue and any other key to stop:\n\n" ;

my $answer = 'y' ;

until ($answer !~ /^y$/i ) {
     getprint("http://132.163.4.101:13") ;
     getprint("http://132.163.4.101:13") ;
     getprint("http://132.163.4.101:13") ;
     getprint("http://132.163.4.101:13") ;
     getprint("http://132.163.4.101:13") ;
     print "Do you  want to continue?  " ;
     $answer = <STDIN>;
     chomp $answer;
} 

print "Good-bye!\n\n" ;
[download]

I like this structure a lot more as it is simple and skips extra vars. Less code == Less bugs. By using a regex match we allow a little more flexibility with lower case or capital 'Y' acceptable.

cheers

tachyon

s&&rsenoyhcatreve&&&s&n\w+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print