Unique records in a text file

I have a 30MB text file (a printer spool file) that has a lot of duplicate information. It basically has the form:

B/M NUMBER: *PAU 00001
00010 xxxxxxxxxxxx
00020 xxxxxxxxxxxx
00030 xxxxxxxxxxxx

B/M NUMBER: *PAU 00002
00010 xxxxxxxxxxxx
00020 xxxxxxxxxxxx
00030 xxxxxxxxxxxx

B/M NUMBER: *PAU 00001
00010 xxxxxxxxxxxx
00020 xxxxxxxxxxxx
00030 xxxxxxxxxxxx

. . .

for many different B/M numbers. Someone suggested Perl could help sort this out and gave me the following three lines:

$/ = "" ;
while (<>) { $Bills{$_}++ };
foreach $Bill (sort keys %Bills) { print $Bill };

I haven't yet figured out how everything in the code works, but it does indeed sort the file very quickly and remove duplicates. However, I'm still not getting the unique ocurrences of the B/Ms themselves. In the case where a page break splits a B/M, there is another header inserted and I have:

B/M NUMBER: *PAU 00001
00010 xxxxxxxxxxxx

B/M NUMBER: *PAU 00001
00020 xxxxxxxxxxxx
00030 xxxxxxxxxxxx
00040 xxxxxxxxxxxx

These B/Ms need to be concatenated somehow and then the duplicates eliminated.

Any suggestions either in Perl or something else?

Patrick

I believe this can be done with JavaScript. You have to use REGULAR EXPRESSIONS and search the file for those expressions. You can then split the string (for your file will be treated as a long string) before and after the REG EXP and concatinate the two again.
You will have to get used to the strict RE syntax.