nitrate: 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/nitrate - from package: python-nitrate

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

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