perl -MDevel::Peek -e " my $a = q!1234!; Dump $a; "
perl -MDevel::Peek -e " my $a = q!1234!; substr$a,0,2,q!!; Dump $a; "
perl -MDevel::Peek -e " my $a = q!1234!; substr($a,0,2)=q!!; Dump $a; "
perl -MDevel::Peek -e " my $a = q!1234!; substr($a,0,2)=q!!; substr$a,0,2,q!!; Dump $a; "
perl -MDevel::Peek -e " my $a = q!1234!; substr$a,0,2,q!!; substr($a,0,2)=q!!; Dump $a; "