grib_to_netcdf: 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/grib_to_netcdf - from package: grib_api

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

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