perl -pi -e  's/XML_SID/My Concretized XML_SID Value/' inifile.xml

#!/usr/bin/perl 
 
use strict; 
use warnings; 
 
use XML::Twig; 
 
sub handle_cdata { 
    my ($twig, $ele) = @_; 
 
    # I had trouble parsing just the #CDATA tags, so I start 
    # a couple of levels up. 
    my $strval = $ele->first_child('strval'); 
    return unless $strval; 
    my $cdata = $strval->first_child('#CDATA'); 
    return unless $cdata; 
 
    if ($cdata->text eq "XML_SID") { 
        # Replace XML_SID meta with something else. 
        my $ncdata = new XML::Twig::Elt( '#CDATA', "My Concretized XML_SID value"); 
        $ncdata->replace($cdata); 
    } 
} 
 
# If other tags besides 'fld's contain stuff you want to 
# transform, put them here. 
my $handlers = { 
    'fld' => \&handle_cdata 
}; 
 
my $twig = new XML::Twig(twig_handlers => $handlers); 
$twig->parsefile("inifile.xml"); 
 
# Change to $twig->flush if you want edit-in-place semantics. Othersise, redirect to a file from the command line. 
$twig->set_pretty_print("indented"); 
$twig->print;