Weird, I'm getting a different output: 
a
b4
d
---
b1
b2
b3
======
a
b7
d
---
b5
b6
======
a
b9
d
---
b8
======
a
bx
d
---
======
---
======

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This is perl 5, version 20, subversion 1 (v5.20.1) built for x86_64-linux-thread-multi

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

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In reply to Re^5: Regex troubles... by choroba
in thread Regex troubles... by kepler

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