You can use a simple scalar reference, then. 

sub alter_var { 
    my $scalar_ref = shift;
    $$scalar_ref =~ s/a/b/;
}

my $scalar = "foobarbaz";
alter_var( \$scalar );

[download]

For more, see perlreftut.

Also note that esskar's second example, which works on $_[0] directly, will alter the scalar passed into the parameter list. (In this case, $_[0] is an alias, not a reference, so there is no need to dereference anything.)

In reply to Re^3: Simple Pass By Reference by friedo
in thread Simple Pass By Reference by tomazos

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