How to mask password when using ALTER USER syntax in psql.

Greetings,

I am using versions 7.4 and 8.3.7.
I have not discovered a way to obfuscate the password when changing it
in psql with ALTER USER syntax.
The password displays in clear text at the command line AND in the log file.
Why is this?
Or am I missing something obvious in the documentation?
Thanks.

Ken Banyas