rpl: 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 CentOS possible default full paths are:

/usr/bin/rpl - from package: rpl

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/rpl - from package: rpl

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

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