Re: ctime vs checksum in copies

[Ed Brown]

One more approach, that doesn't require any file copying or tempfile
storage, is to build the file entirely with cfengine, like this yum.conf
example, where 3 variables are set depending on network segment, server
class, and whether it's a 'new build' or not:

  { /etc/yum.conf
    EmptyEntireFilePlease
    AppendIfNoSuchLine      "[main]"
    AppendIfNoSuchLine      "cachedir=/var/cache/yum"
    AppendIfNoSuchLine      "pkgpolicy=newest"
    AppendIfNoSuchLine      "tolerant=1"
    AppendIfNoSuchLine      "exactarch=1"
    AppendIfNoSuchLine      "retries=3"
    AppendIfNoSuchLine      "exclude=${YumExcludes}"
    AppendIfNoSuchLine      "${LogString}"
    AppendIfNoSuchLine      "[base]"
    AppendIfNoSuchLine      "name=${packageserver} common rpm
repository"
    AppendIfNoSuchLine      "baseurl=ftp://${packageserver}";
    AutoCreate
 }

As with some of the other examples, cfengine doesn't actually rewrite
the file unless it's necessary.  This is well-suited for short files,
would be a little bit of a pain to generate long files this way.

-Ed