luac50: 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/luac50 - from package: lua50

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

Error in other languages:
luac50: bevel nie gevind nie
luac50: comandă negăsită
luac50: comando não encontrado
luac50: commande introuvable
luac50: command not found
luac50: käsku ei ole
luac50: không tìm thấy lệnh
luac50: komanda nerasta
luac50: Kommando nicht gefunden.
luac50: kommandot finns inte
luac50: komut yok
luac50: nie znaleziono polecenia
luac50: níor aimsíodh an t-ordú
luac50: no se encontró la orden
luac50: no s'ha trobat l'ordre
luac50: opdracht niet gevonden
luac50: parancs nem található
luac50: perintah tidak ditemukan
luac50: príkaz nenájdený
luac50: příkaz nenalezen
luac50: команда не найдена
luac50: командата не е открита
luac50: 命令找不到
luac50: コマンドが見つかりません