I assume he was performing some sort of authenticated action - e.g. against the svn repository - and providing the password as a command-line argument rather th

I assume he was performing some sort of authenticated action - e.g. against the svn repository - and providing the password as a command-line argument rather than interactively. This would not only leave the password in the history, but would make it visible to anyone else on the machine who runs ps whilst the command is executing. It's terrible security practice, but I've seen it done more times than I can count.