It currently lives http://code.google.com/p/mlox/wiki/Tes3cmd, where you can find instructions for download/install/usage and so on.
A new version is coming soon with bugfixes and new features.
tes3cmd allows you to do various things, like:
- Clean plugins (probably one of the most useful features for regular users)
- Generate a "multipatch" for leveled lists and more
- Convert a plugin or savegame to readable text (handy for understanding plugins)
- Global search and replace
- Global modification of records via small scripts written in Perl
- Much, much more
Previous threads: http://www.gamesas.com/topic/934107-relz-tes3cmd-a-small-tool-for-modifying-tes3-plugins/, http://www.gamesas.com/topic/1395562-relz-tes3cmd-a-small-tool-for-modifying-tes3-plugins/.