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my $v = 'DA39A3EE5E6B4B0D3255BFEF95601890AFD80709'; my $m = 'FFFF804020100804020100804020100804000102'; ... print unpack 'H*', pack 'B*', $rb; da39804000000804020100800020100004000100
perl -le"print unpack'H*', pack'B*', unpack('B*',pack'H*','DA39A3EE5E6B4B0D3255BFEF95601890AFD80709') & unpack('B*',pack'H*','FFFF804020100804020100804020100804000102')" da39804000000804020100800020100004000100