mdmdetect: 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/sbin/mdmdetect - from package: xtel

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

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