remove duplicate lines in a file

[jack777]

Hi
Having a file as follows

==================================================
Date           Time         error code      server 
======================================================
12-29-08    10:10        121221          server A
12-29-08    10:12        121221          server A
12-29-08    10:10        121221          server B
12-29-08    10:10        121221          server c

Need to remove the duplicate lines with the following conditions

if date=12-29-08 and server=server A .
Must delete the line with old time and keep the latest.

anyone can suggest

Thanks in advance

[burschik]

#!/bin/awk

BEGIN { pattern = /^[[:digit:]]+-[[:digit:]]+-[[:digit:]]/; }

$1 !~ pattern { print; }

$1 ~ pattern {
if ($1 != previous_date && previous_date != "" ||
$5 != previous_server && previous_server != "") {
print previous_line;
}

previous_date = $1;
previous_server = $5;
previous_line = $0;
}

END { print previous_line; }