drone: 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/drone - from package: ostinato

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

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