ja-rule: 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/ja-rule - from package: ola-ja-rule

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

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