You mean "common" SHA512 which is [a-f0-9]{128} string but this is a Unix SHA512 implementation produced by crypt() function. Unix / crypt() type hashes look like "$x$yyyyyyy$zzzzzz...zzzzz" where "x" is a hash type, "yyyyyyyy" is a salt, and "zzz......zzz" is a hash string itself. You may already seen something like "$1$dh8cho7m$XMuMathohL8eek8yaLG9P0T/" which is a Unix MD5 hash while "common" MD5 hash is a [a-f0-9]{32} string. More info: http://man7.org/linux/man-pages/man3/crypt.3.html

Wat