I'm not a pro at this but here is where I might start playing around with it (the character classes suggested already was also a good idea). 

perl -Mcharnames=all -le 'printf "%5d -> \\x{%04x} -> %s\n", $_, $_, c
+harnames::viacode($_) for 4,127'
    4 -> \x{0004} -> END OF TRANSMISSION
  127 -> \x{007f} -> DELETE

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In reply to Re: How to include escape sequence characters in regular expressions? by Your Mother
in thread How to include escape sequence characters in regular expressions? by pat_mc

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