G'day ibm1620,

"Your final print is a real head-scratcher, but I like what it does and I'll noodle on it some more...."

I'm assuming "final print" refers to:

print "$out\n" =~ s/ $//r =~ s/.{65}\K /\n/gr;
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I don't know which bit, or bits, you're having difficulties with. One, or both, of these references might help:

perlop: Regexp Quote-Like Operators: s/PATTERN/REPLACEMENT/msixpodualngcer

• The /r option indicates non-destructive substitution.
• These can be chained; e.g. s///r =~ s///r =~ s///r
• The same option also exists for transliteration: "perlop: Quote-Like Operators: y/SEARCHLIST/REPLACEMENTLIST/cdsr".
• These can also be chained; e.g. y///r =~ y///r =~ y///r
• You can also mix chaining; e.g. s///r =~ y///r =~ s///r =~ y///r
• Introduced in 5.14: "perl5140delta: Non-destructive substitution".

perlrebackslash: Misc: \K

• The \K escape sequence indicates that everything to its left should be kept.
• See also "perlre: Extended Patterns: Lookaround Assertions: \K".
• Introduced in 5.10: "perl5100delta: Core Enhancements: Regular expressions: \K escape".

I've shown the versions where /r and \K were introduced. With your stated 5.34.1 version, both of these will be available to you. I included this information for those using older versions of Perl.