shef: 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/shef - from package: chef

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

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