rip98d: 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/rip98d - from package: ax25-tools

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

Error in other languages:
rip98d: bevel nie gevind nie
rip98d: comandă negăsită
rip98d: comando não encontrado
rip98d: commande introuvable
rip98d: command not found
rip98d: käsku ei ole
rip98d: không tìm thấy lệnh
rip98d: komanda nerasta
rip98d: Kommando nicht gefunden.
rip98d: kommandot finns inte
rip98d: komut yok
rip98d: nie znaleziono polecenia
rip98d: níor aimsíodh an t-ordú
rip98d: no se encontró la orden
rip98d: no s'ha trobat l'ordre
rip98d: opdracht niet gevonden
rip98d: parancs nem található
rip98d: perintah tidak ditemukan
rip98d: príkaz nenájdený
rip98d: příkaz nenalezen
rip98d: команда не найдена
rip98d: командата не е открита
rip98d: 命令找不到
rip98d: コマンドが見つかりません