$ perl -Mstrict -Mwarnings -E ' my $x = q{çe quil Y a Yå}; $x =~ s/([[:^ascii:]])/unpack q{H2}, $1/eg; say $x; ' c383c2a7e quil Y a Yc383c2a5 #### $ perl -Mstrict -Mwarnings -E ' my $x = q{çe quil Y a Yå}; $x =~ s/([[:^ascii:]])/q{<} . unpack(q{H2}, $1) . q{>}/eg; say $x; ' <83>e quil Y a Y<83>