MX-calibrate: 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/MX-calibrate - from package: pyfai

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

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