natus: 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/natus - from package: natus

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

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