Newbie Question About System Update

[Warner Losh]

> Fact is, trying to update a running system could result in silent failures.
> The system can not replace programs that are in use, so there's always the
> chance that something or other won't get updated (cron would be an excellent
> example ... do you always shut cron off when you update?  How about syslogd?)

Actually, it can.  install goes to great lengths to make sure that it
carefully moves the executable out of the way before replacing it.  It
won't go away until the last process to be executing out of it goes
away.

> That being said, I quite often do installworld on running systems because I
> have no way to go to single-user mode.  It almost always works well enough
> for my purposes, but I don't want anyone to think that it's "OK" to do this,
> as it's not guaranteed to work, and will most likely result in some programs
> not being updated (such as the examples in the previous paragraphs).

It usually works well enough most of the time.  I do it all the time
on my development machines.  The problem is "well enough" and "most of
the time."

Warner