kumoctl: command not found

Have You tried accessing the binary with the full path?

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/kumoctl - from package: kumofs

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