bug#13144: "comm" bug or strange behaviour

[Matteo Zambelli]

Hi, i was trying to find common lines between the two attached
files(both created with "dpkg --get-selections > filename.txt") with
this command:

comm -12 squeeze-xfce-installed_packages.txt
squeeze-xfce-installed_packages.txt > result.txt

then i noticed that the line:

libcdio10                                       install

that is regularly present in both files, doesn't appear in the
result(as well as few other lines).
I have tried with option "--nocheck-order" and such, but those common
lines are still missing in the output file.

Here's my uname -a:
Linux wheezy-dvd-exp 3.2.0-4-686-pae #1 SMP Debian 3.2.32-1 i686 GNU/Linux

Thanks for help ;)

squeeze-xfce-installed_packages.txt
Description: Text document

squeeze-lxde-installed_packages.txt
Description: Text document