Python and Daemons

Cameron Laird claird at
Tue Feb 26 10:30:45 EST 2002

In article <mailman.1014484778.28709.python-list at>,
Justin Sheehy  <justin at> wrote:
>mrchameleon at (Chris Reay) writes:
>>> This is what I use:
>> ... and an attribution to W. Richard Stevens is also considered good mojo.
>True enough.  Everyone who is going to do any serious network
>programming or much of anything on UNIX should read his books.
>A few of his idioms have become so standard that I sometimes
>forget to make the attribution explicit.
>Thank you, Richard.  You are missed.
'Worth repeating.  See <URL: >
for details.

I'll add a few words on the subject of daemons.  Daemons
roughly correspond to what Win* people call "services".
Some Unixois use the word loosely to mean, "long-running
process" or even, in an extreme case, "anything in the
background".  Stevens' heritage generally intends "daemon"
only in a more restricted sense, involving these notions,
but also including specific signal- and I/O-handling qual-
ifications, and umask and process group leader assignment.

The first surprise Pythoneers typically have in "daemonizing",
though, is to discover an unsuspected dependence on environ-
ment variables.  Daemons typically run disconnected from any
TTY, and they also have minimal environment dictionaries (to
mix metaphors slightly).  The latter often flushes out
forgotten assumptions about PATH, *LIB*PATH, and so on.

Cameron Laird <Cameron at>

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