certmaster: 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/certmaster - from package: certmaster

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

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