On Tue, 3 Dec 1996, Joel Klecker wrote:

(Q:  Does this update binaries currently in use(i.e. /bin/sh or
/bin/csh)?)

Hope I'm remembering the terminology right on this one. I believe it will
update even currently running binaries, though not the copy in memory.
For that reason, you'd have to reboot after doing this to see some of
those behavioral changes (i.e. changes to any running daemons or the
kernel), log out and back in to see others (i.e. changes to /bin/sh).
--unlink (AFAIK) makes a call to the unlink system call, which deletes the
files, allowing the on-disk copies to be effectively replaced, but the
individual inodes cannot be reused until the file is closed, thus
providing an access path to the old copy of the file for any file
descriptors currently open, and an access path to the new copy for any
future file descriptors, thus, quitting sh and rerunning it would suddenly
change versions, even though the copy on disk had been changed hours ago.

Hope that helps more than it confuses,

 /---------------------------------------------------------------------\
|David A. Gatwood             And Richard Cory, one calm summer night,  |
|davagatw@mars              Went home and put a bullet through his head.|
|dgatwood@nyx.cs.du.edu              --Edwin Arlington Robinson         |
|http://mars.utm.edu/~davagatw -or- http://nox.cs.du.edu:8001/~dgatwood |
 \---------------------------------------------------------------------/