spyder3: 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/spyder3 - from package: spyder3

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

Error in other languages:
spyder3: bevel nie gevind nie
spyder3: comandă negăsită
spyder3: comando não encontrado
spyder3: commande introuvable
spyder3: command not found
spyder3: käsku ei ole
spyder3: không tìm thấy lệnh
spyder3: komanda nerasta
spyder3: Kommando nicht gefunden.
spyder3: kommandot finns inte
spyder3: komut yok
spyder3: nie znaleziono polecenia
spyder3: níor aimsíodh an t-ordú
spyder3: no se encontró la orden
spyder3: no s'ha trobat l'ordre
spyder3: opdracht niet gevonden
spyder3: parancs nem található
spyder3: perintah tidak ditemukan
spyder3: príkaz nenájdený
spyder3: příkaz nenalezen
spyder3: команда не найдена
spyder3: командата не е открита
spyder3: 命令找不到
spyder3: コマンドが見つかりません