relevation: 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/relevation - from package: relevation

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

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