hmac256: 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/hmac256 - from package: libgcrypt-devel

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

On Debian possible default full paths are:

/usr/bin/hmac256 - from package: libgcrypt20-dev

You may install the required package with command apt-get install {package}

Error in other languages:
hmac256: bevel nie gevind nie
hmac256: comandă negăsită
hmac256: comando não encontrado
hmac256: commande introuvable
hmac256: command not found
hmac256: käsku ei ole
hmac256: không tìm thấy lệnh
hmac256: komanda nerasta
hmac256: Kommando nicht gefunden.
hmac256: kommandot finns inte
hmac256: komut yok
hmac256: nie znaleziono polecenia
hmac256: níor aimsíodh an t-ordú
hmac256: no se encontró la orden
hmac256: no s'ha trobat l'ordre
hmac256: opdracht niet gevonden
hmac256: parancs nem található
hmac256: perintah tidak ditemukan
hmac256: príkaz nenájdený
hmac256: příkaz nenalezen
hmac256: команда не найдена
hmac256: командата не е открита
hmac256: 命令找不到
hmac256: コマンドが見つかりません