cudf-check: 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/cudf-check - from package: cudf-tools

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

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