cereal-admin: 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/cereal-admin - from package: cereal

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

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