ralsh: 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/ralsh - from package: puppet

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

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