In all likelyhood, all you need to do is change the codepage of the CLI session.

For example, the default codepage on my system is 850, and if I print your test string:

#! perl -slw
use strict;

my $str = "abc123äöüß";

print $str;
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this is what I get:

C:\test>chcp
Active code page: 850

C:\test>1140216.pl
abc123õ÷³▀

But if I change the codepage to the Windows Unicode codepage 65000, I get this:

C:\test>chcp 65000
Active code page: 65000

C:\test>1140216.pl
abc123äöüß

And if you need to automate the change of codepage, use:

use Win32::Console;
...
Win32::Console::OutputCP( 65000 );
...
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BTW: The above was done using perl 5.10; and still works as is with more modern versions:

C:\test>\perl5.18\perl\bin\perl.exe 1140216.pl
abc123äöüß

C:\test>\Perl5.20\bin\perl.exe 1140216.pl
abc123äöüß

C:\test>\Perl22\bin\perl.exe 1140216.pl
abc123äöüß
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