>perl -wMstrict -le "print unpack 'H*', pack 'N', -0; print unpack 'H*', pack 'N', -1; print unpack 'H*', pack 'N', -2; print unpack 'H*', pack 'N', -9; print unpack 'H*', pack 'N', -10; print ''; ;; print unpack 'H*', pack 'N', ~0; print unpack 'H*', pack 'N', ~1; print unpack 'H*', pack 'N', ~2; print unpack 'H*', pack 'N', ~9; print unpack 'H*', pack 'N', ~10; " 00000000 ffffffff fffffffe fffffff7 fffffff6 ffffffff fffffffe fffffffd fffffff6 fffffff5