derbyctl: 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/derbyctl - from package: derby-tools

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

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