luatex: 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/luatex - from package: texlive-binaries

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

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