secon: 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/secon - from package: policycoreutils

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

On Debian possible default full paths are:

/usr/bin/secon - from package: policycoreutils

You may install the required package with command apt-get install {package}

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