rip: 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/rip - from package: morituri

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

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