scalac: 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/scalac - from package: scala

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

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