nc3tonc4: 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/nc3tonc4 - from package: netcdf4-python

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

Error in other languages:
nc3tonc4: bevel nie gevind nie
nc3tonc4: comandă negăsită
nc3tonc4: comando não encontrado
nc3tonc4: commande introuvable
nc3tonc4: command not found
nc3tonc4: käsku ei ole
nc3tonc4: không tìm thấy lệnh
nc3tonc4: komanda nerasta
nc3tonc4: Kommando nicht gefunden.
nc3tonc4: kommandot finns inte
nc3tonc4: komut yok
nc3tonc4: nie znaleziono polecenia
nc3tonc4: níor aimsíodh an t-ordú
nc3tonc4: no se encontró la orden
nc3tonc4: no s'ha trobat l'ordre
nc3tonc4: opdracht niet gevonden
nc3tonc4: parancs nem található
nc3tonc4: perintah tidak ditemukan
nc3tonc4: príkaz nenájdený
nc3tonc4: příkaz nenalezen
nc3tonc4: команда не найдена
nc3tonc4: командата не е открита
nc3tonc4: 命令找不到
nc3tonc4: コマンドが見つかりません