hi, The following regular expression will work 
my $test = 'x x x a x x x b x x x a x x x b x x x';
$test =~ tr/[ab]/[ba]/;
print "$test";:w

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In reply to Re: Multiple replacements with the exception of previously made replacements. by sanku
in thread Multiple replacements with the exception of previously made replacements. by jthiel

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