sha512hmac: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/sha512hmac - from package: hmaccalc

You may install the required package with command yum install {package}

Error in other languages:
sha512hmac: bevel nie gevind nie
sha512hmac: comandă negăsită
sha512hmac: comando não encontrado
sha512hmac: commande introuvable
sha512hmac: command not found
sha512hmac: käsku ei ole
sha512hmac: không tìm thấy lệnh
sha512hmac: komanda nerasta
sha512hmac: Kommando nicht gefunden.
sha512hmac: kommandot finns inte
sha512hmac: komut yok
sha512hmac: nie znaleziono polecenia
sha512hmac: níor aimsíodh an t-ordú
sha512hmac: no se encontró la orden
sha512hmac: no s'ha trobat l'ordre
sha512hmac: opdracht niet gevonden
sha512hmac: parancs nem található
sha512hmac: perintah tidak ditemukan
sha512hmac: príkaz nenájdený
sha512hmac: příkaz nenalezen
sha512hmac: команда не найдена
sha512hmac: командата не е открита
sha512hmac: 命令找不到
sha512hmac: コマンドが見つかりません