dune: 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/dune - from package: whitedune

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

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