beef: 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/bin/beef - from package: beef

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

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