sevmgr_demo: 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_demo - from package: sevmgr

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

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