Pattern matching: LAST HELP!

Thanks a lot for your help.I have the last problem to resolve.
The script:
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#!/usr/bin/perl
$_ = q(
Apr 22 01:03:01 pandora ipop3d[28245]: Login user=holy00
Apr 21 01:03:01 pandora ipop3d[28245]: Login user=holy01
Apr 21 01:03:01 pandora ipop3d[28245]: Login user=holy05
Apr 21 01:03:01 pandora ipop3d[28245]: Login user=holy01
Apr 21 01:03:01 pandora ipop3d[28245]: Login user=holy00
Apr 21 01:03:01 pandora ipop3d[28245]: Login user=holy02
Apr 21 01:03:01 pandora ipop3d[28245]: Login user=holy05
Apr 21 01:03:01 pandora ipop3d[28245]: Login user=holy01
Apr 21 01:03:01 pandora ipop3d[28245]: Login user=holy00
);
for (split/\n/) {s~(.+user=)(.+)~$2~; $users{$_} = x}
for (sort keys %users) {print "$_$/"}
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is perfect,but I didn't copy the last part of the line:
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Apr 14 17:24:45 pandora ipop3d[6577]: Login user=ct000512 host=ppp-62-11-119-90.dialup.tiscali.it
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How can extract now just the user name?
And how is possible to use a big file(maillog) instead of the log lines?
Another times many thanks.