$ perl -Mstrict -Mwarnings -e ' binmode STDOUT => ":utf8"; my $subs = join q{} => map chr, 0x430, 0x431, 0x446, 0x410, 0x411, 0x426; while (<>) { s/@([^@]+)@/"\$_ = \$1; y{abcABC}{$subs}; \$_"/eeg; print; } '