lxc-device: 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/lxc-device - from package: lxc

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

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