...
my $abc = 'test';

machwas_1($abc);

machwas_2(\$abc);

machwas_3('test');


sub machwas_1 {
    my $xyz = shift;
    # ...mach irgend was
}


sub machwas_2 {
    my $xyz = shift;
    # ...mach irgend was
}


sub machwas_3 {
    my $xyz = shift;
    # ...mach irgend was
}
...