mup: 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/mup - from package: mup

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

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