$ LANG=C sudo apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages have been kept back:
  libvcdinfo0 totem-xine ttf-dejavu
The following packages will be upgraded:
1 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
47 not fully installed or removed.
Need to get 0B/258kB of archives.
After unpacking 41.0kB of additional disk space will be used.
Do you want to continue [Y/n]?
Reading package fields... Done
Reading package status... Done
Retrieving bug reports... Done
Parsing Found/Fixed information... Done
Reading changelogs... Done
(Reading database ... 146581 files and directories currently installed.)
Preparing to replace net-tools 1.60-17 (using .../net-tools_1.60-17.1_i386.deb) ...
Unpacking replacement net-tools ...
dpkg: error processing /var/cache/apt/archives/net-tools_1.60-17.1_i386.deb (--unpack):
 trying to overwrite `/usr/share/locale/ja/LC_MESSAGES/', which is also in package ja-trans
dpkg-deb: subprocess paste killed by signal (Broken pipe)
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)

ja-transってどこかで見たなぁと思ったら、 これ でした。で、ja-transを削除したら、無事アップデート完了。