seunshare: 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/sbin/seunshare - from package: policycoreutils-sandbox

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

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