ree: 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/ree - from package: ree

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

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