$ perl -le'
my $x = "AAAAAXXXXXXXAAAXXXXXAXXXXAAAA";
print $x;
$x =~ s/(?<=A)X+(?=A)/ "A" x ( $+[0] - $-[0] ) /eg;
print $x;
'
AAAAAXXXXXXXAAAXXXXXAXXXXAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAA

[download]

Or: 

$ perl -le'
my $x = "AAAAAXXXXXXXAAAXXXXXAXXXXAAAA";
print $x;
$x =~ s/(?<=A)X+(?=A)/@{[ "A" x ( $+[0] - $-[0] ) ]}/g;
print $x;
'
AAAAAXXXXXXXAAAXXXXXAXXXXAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAA

[download]

In reply to Re: Replace all characters inbetween by jwkrahn
in thread Replace all characters inbetween by Anonymous Monk

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