supernova: 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/supernova - from package: supercollider-supernova

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

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