systune: 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/sbin/systune - from package: systune

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

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