GenSec: 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/GenSec - from package: edk2-tools

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

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