not quite. you need something like
dd if=/dev/null of=/dev/xxx bs=verybig conv=sync
Unix weenies of old will recall "clri" to clear an inode. If paranoia is in effect, try something like the following:
ls -li remailer-log or whatever to get the i-node number, then clri /dev/sdxx #_of_i-node
this will zero out the inode it also does NOT clear the data blocks just the inode pointers to the data blocks. infact if you do this. (this you *will* need to umnount and fsck your system [or reboot if you did this to you root partition]). in fact if you do this with out deleteing the file first you run a good chance of crashing the system. normaly I would say "do not try this at home" but then I would rather you shot yourself in the foot at home (as opposed to shooting yourself and who ever is on a public system) I will post some C/Perl code that will work as a /bin/rm replacement in a few days. -Pete