Supposed, we got the YAGNI case, and all you need is In that case, you could do it like this: 
use Getopt::Std;
my %opts;

getopts( 'dhc:', \%opts );      # usw, -c for cfg-file
$opts{'c'} and $opts{'c'} !~ m{^/([\w\.]+/)*[\w\.]+$} and &usage;

my $cfg = $opts{'c'} ? $opts{'c'} : '/default/path/to.conf';

open CFG, '<'.$cfg or die;
while(<CFG>) {
   # do sth like ...
   /^\s*(.*?)\s*: (.*)$/;  
   $cfg{ $1 } = $2;
}
foreach (keys %cfg) {
   $opts{$_} and $cfg{$_} = $opts{$_};
}

[download]

You can do this "overriding" as many times you like, using a list of config file locations. The script would eat one file after another, starting with the "weakest", most global one, and finishing with the command line options.

The overriding process could be done in the manner indicated in the code above.

In reply to Re^2: Config File Shuffle by mantadin
in thread Config File Shuffle by pileofrogs

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.