If you are not stuck using Config::IniFile and can switch to Config::General, then you get variable substitution built in.

use Config::General;
use Data::Dumper;

$conf = new Config::General(
                -ConfigFile => 'y.cfg',
                -InterPolateVars => 1,
                );

my %config = $conf->getall;

print Dumper(\%config);

__END__


# config file contents

# GENERAL
# scoping allows substituting in the same block or
# a nested block, see N.B. below.
scheduledb=e:\users\dbush\schedule.db

<SERVICE>
debug=1
interval=5
start1=browser.exe;browser;NORMAL_PRIORITY_CLASS
start2=schedule.exe;schedule "localhost:$scheduledb";NORMAL_PRIORITY_C
+LASS
</SERVICE>


########### Output: $VAR1 = \%config
### note how $scheduledb is substituted into 'start2'
$VAR1 = {
          'SERVICE' => {
                         'start1' => 'browser.exe;browser;NORMAL_PRIOR
+ITY_CLASS',
                         'start2' => 'schedule.exe;schedule "localhost
+:e:\\users\\dbush\\schedule.db";NORMAL_PRIORITY_CLASS',
                         'interval' => '5',
                         'debug' => '1'
                       },
          'scheduledb' => 'e:\\users\\dbush\\schedule.db'
        };
[download]

N.B. One thing to watch out for is scoping your name-value pairs. For all the details about scoping for interpolation, check out Config::General::Interpolated.

--
hiseldl
What time is it? It's Camel Time!