yhsm-linux-add-entropy: 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 Debian possible default full paths are:

/usr/sbin/yhsm-linux-add-entropy - from package: yhsm-tools

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

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