Hello hadrons, I haven't used Windows in over 20 years but these may work.

(Obviously I can't test these because ... no Windows)

system ('grep -l "DATAmessage.*3\.0" *.xml > 3.0_files_arraydata.txt')
+;
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open my $FH, '>', '3.0_files_arraydata.txt'
    or die "Cannot open '3.0_files_arraydata.txt' because: $!";

{   local @ARGV = <*.xml>
        or die "Cannot find any '*.xml' files\n";

    while ( <> ) {
        if ( /DATAmessage.*3\.0/ ) {
            print $FH "$ARGV\n";
            close ARGV;
            }
        }
    }
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system ("mv temp_3.0_files_onixarraydata.txt 3.0_files_arraydata.txt")
+;
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rename 'temp_3.0_files_onixarraydata.txt', '3.0_files_arraydata.txt'
    or die "Cannot move 'temp_3.0_files_onixarraydata.txt' because: $!
+";
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system ("cat *files_arraydata.txt > data2.txt");
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open my $FH, '>', 'data2.txt'
    or die "Cannot open 'data2.txt' because: $!";

{   local @ARGV = <*files_arraydata.txt>
        or die "Cannot find any '*files_arraydata.txt' files\n";

    print $FH $_ while <>;
    }
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system ("rm data2.txt");
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unlink 'data2.txt'
    or die "Cannot delete 'data2.txt' because: $!";
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system ("sort -u data2.txt > data.txt");
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open my $IN,  '<', 'data2.txt'
    or die "Cannot open 'data2.txt' because: $!";

open my $OUT, '>', 'data.txt'
    or die "Cannot open 'data.txt' because: $!";

{   my %unique;

    print $OUT sort grep { ! $unique{ $_ }++ } <$IN>;
    }
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