Perl regex to parse out the swinstall.hosts from /.sw/defaults.hosts

Perl regex to parse out the swinstall.hosts from /.sw/defaults.hosts The string can be like this

swinstall.hosts = {ws01 s003 s002 s001 a7altsrv a7server}

or

swinstall.hosts = {
s004
s001sdb1
s003
s002p1
s002
ws01
s001p1
s001
a7server
}

Ie. The code needs to deal with line breaks

undef $/;
open(DH, "</.sw/defaults.hosts") or die "unable to open default.hosts\n";
$file = <dh>;
close(DH);
$file =~ m/
  swinstall\.hosts # Match the beginning of the hosts we want
  (?:.*?) # followed by a space or not. Minimal match
  =       # followed by an '='
  (?:.*?) # followed by a space or not. Minimal match
  {       # followed by the open brace to begin the list of hosts
  (.*?)   # followed by some characters which are the 
          # hostnames saved into a back reference
  } # followed by the close brace
 /six;
print $1 . "\n";