On windows, you can use an API to retrieve the command line used to start the current process. You can get at this API through either Inline::C or Win32::API:

use Inline C => Config => BUILD_NOISY => 1;
use Inline C => <<'END_C',  NAME => 'junk', CLEAN_AFTER_BUILD => 0;

SV *getCommandLine( ) {
    return newSVpv( GetCommandLine(), 0 );
}

END_C

print getCommandLine();

__END__
C:\test>getCmdLine.pl -x -P -Mfred /some=other
"C:\Perl64\bin\perl.exe" "C:\test\getCmdLine.pl"  -x -P -Mfred /some=o
+ther
[download]