nopt: 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/nopt - from package: nodejs-nopt

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

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