scss: 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/scss - from package: ruby-sass

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

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