sevmgr: 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/sevmgr - from package: sevmgr

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

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