mifare-classic-write-ndef: 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/mifare-classic-write-ndef - from package: libfreefare-bin

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

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