pynag: 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/pynag - from package: pynag

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

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