Note also that  \cA is an alternate representation of 'control-A' both in and out of a character class.

>perl -wMstrict -le
"my $s = qq{fee\x01fie\x01foe};
 $s =~ s{ [\cA] }{--}xmsg;
 print $s;
 my $t = qq{biz\cAbaz\cAboz};
 $t =~ s{ \x01 }{++}xmsg;
 print $t;
"
fee--fie--foe
biz++baz++boz
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