Sample code avoid duplicate in the way you like.

%avoid_dup = ();
while ( <DATA> ) {
  my ($drive,$name) = split(/:/);
  if ( $avoid_dup{$name} ne '1' ) {
    #do some stuufs 
    $avoid_dup{$name} = 1;
  }
}

_DATA_
D:/myfiles/Test/
E:/pics/cgi-bin/new/
C:/temp/
D:/new/files/
F:/new/more/
C:/test/cgi-bin/ac/^ok
C:/new/files/   # This line shouldn't be allowed here, it is duplicate
+d.
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