dog: 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/dog - from package: sheepdog

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

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