ipcontroller3: 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/ipcontroller3 - from package: ipython3

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

Error in other languages:
ipcontroller3: bevel nie gevind nie
ipcontroller3: comandă negăsită
ipcontroller3: comando não encontrado
ipcontroller3: commande introuvable
ipcontroller3: command not found
ipcontroller3: käsku ei ole
ipcontroller3: không tìm thấy lệnh
ipcontroller3: komanda nerasta
ipcontroller3: Kommando nicht gefunden.
ipcontroller3: kommandot finns inte
ipcontroller3: komut yok
ipcontroller3: nie znaleziono polecenia
ipcontroller3: níor aimsíodh an t-ordú
ipcontroller3: no se encontró la orden
ipcontroller3: no s'ha trobat l'ordre
ipcontroller3: opdracht niet gevonden
ipcontroller3: parancs nem található
ipcontroller3: perintah tidak ditemukan
ipcontroller3: príkaz nenájdený
ipcontroller3: příkaz nenalezen
ipcontroller3: команда не найдена
ipcontroller3: командата не е открита
ipcontroller3: 命令找不到
ipcontroller3: コマンドが見つかりません