Subject: Re: power management and related concerns
To: Chris Jepeway <>
From: Garrett D'Amore <>
List: tech-kern
Date: 07/03/2006 21:51:02
Chris Jepeway wrote:
> On Jul 3, 2006, at 6:31 PM, Garrett D'Amore wrote:
>> A few ways to make editing XML more friendly:
> "From the wild O'Flaherties, O Lord, defend us"...
>>     1) provide a vixml  wrapper which takes a DTD and checks for DTD
>> compliance before saving the file.  (It would work with a temporary
>> file, and could do file locking ala "vipw")
> And an edxml.  And an exxml.  And an awkxml.  And an emacsxml.
> And a jotxml.  And a picoxml.  And a sedxml.  And a shxml.  And
> a cshxml.  And...ugh.

Hmph.  Don't see sedpw, cshpw, etc.

> Please stay away from XML for system-level configs, particularly
> ones like powerd/sysmon/whosie-whatsis that can take my machine down
> from underneath me.  I think XML pretty much rules out quick-n-dirty
> shell-fu saving the day in such cases, and I think that might be bad.

Do we really think that any of these config files are likely to grow to
the complexity _and_ the power where a simple edit by a human can't get
one to a sane state?

And, if necessary, we can provide some simple xml command line editing
tools for use in scripting.  Possible example strawmen:

    xml -get -d printcap -f /etc/passwd.xml "user=garrett" "gecos"
    xml -set -d printcap -f /etc/printcap.xml "queue=lp"  "device=/dev/lp0"

I've also written awk and sed code that can manipulate certain bits of
XML.  Its not hard to do at all, but it does require a little more
effort and its "hard" if the format is not constrained to some
reasonable subset.  But things like password files could easily be
constrained to a simple format that is a proper subset of XML, and then
you _could_ use your shell-fu to hack on them.

I'm not a huge fan of XML, but your objections here sound like FUD much
more than any complaint, and I've not heard any better suggestions for a
file format that can be easily extended or support a variety of uses.

Again, I'm not beholden to XML, but I _abhor_ the idea of creating
another one-off, non-extensible special purpose file format.

    -- Garrett

> Chris <>.

Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
Phone: 951 325-2134  Fax: 951 325-2191