You can keep Linux from recording a command history by prepending one or more spaces in front of the command.
./novacoind walletpassphrase iamapassword 100000
Would be recorded in the bash history.
./novacoind walletpassphrase iamapassword 100000
Would not be recorded in the bash history.
Only if you have set HISTCONTROL with "ignorespace" which is not the default.
Edit: this is assuming you use bash and not another shell (I don't know others well enough).
Hmm, strange as it always appears to be the default to me.
For example from my current VM bash.rc file:
# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth
# append to the history file, don't overwrite it
shopt -s histappend
# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000
Ahh well, it is easy enough to test for:
robert@vm:/$ echo "This is normal"
This is normal
robert@vm:/$ echo "This is normal"
This is normal
robert@vm:/$ echo "This is hidden"
This is hidden
robert@vm:/$ echo "This is normal"
Well, anyway I believe this particular poster would feel much safer mining to a separate wallet (encrypted or otherwise) and just transferring the coins to his real wallet every day/hour whatever.

Also:
Balthazar....what the heck did you do to bury the dam address version setting in your fork of ABE?
I have been trying all afternoon to get it set up and on CCE . I have tried all the normal places where the address version is declared, however no matter where I place (\x08 or 08..same in Dec as Hex) the addresses are wrong, everything else is right.
You just don't want anybody else to have a NVC explorer up....DO you?

On that note: The newest version of ABE has some interesting new features you might want to check out. All the explorers except for NVC on CCE are using it. I did not feel like reinventing the wheel by converting your NVC fork to the latest ABE client.
Hopefully, I will have NVC up on CCE tonite, everything is set and ready except for the address version issue...thing...roadblock...
