Best to avoid the needless, troublesome, expensive lookbehind by replacing (?<=FOO)BAR with FOO\KBAR. 

perl -e 'my $var = "hello"; $var =~ s!\D[01] file\Ks!!ig;'

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Requires 5.10+

In reply to Re: Lookbehind issues with unicode by ikegami
in thread Lookbehind issues with unicode by mrbark

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