| I need to extact the user name of every user who is logged in
| /var/log/maillog.I just want the user name and every one must be present
| just one time.
| Now I can extract all the strings with the user name and every name is
| repeated many times.What can I do?Thanks a lot
Make each user the key of a hash, as follows:
$_ = q(
Apr 21 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 "$_$/"}
(ie. Make an array of paragraphs (if necessary), extract the user pattern
from each item and make it the key of the hash %users with value x or
anything. A key cannot be duplicated. Sort the keys if you want.)
JD
