wgrib2: 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/wgrib2 - from package: wgrib2

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

Error in other languages:
wgrib2: bevel nie gevind nie
wgrib2: comandă negăsită
wgrib2: comando não encontrado
wgrib2: commande introuvable
wgrib2: command not found
wgrib2: käsku ei ole
wgrib2: không tìm thấy lệnh
wgrib2: komanda nerasta
wgrib2: Kommando nicht gefunden.
wgrib2: kommandot finns inte
wgrib2: komut yok
wgrib2: nie znaleziono polecenia
wgrib2: níor aimsíodh an t-ordú
wgrib2: no se encontró la orden
wgrib2: no s'ha trobat l'ordre
wgrib2: opdracht niet gevonden
wgrib2: parancs nem található
wgrib2: perintah tidak ditemukan
wgrib2: príkaz nenájdený
wgrib2: příkaz nenalezen
wgrib2: команда не найдена
wgrib2: командата не е открита
wgrib2: 命令找不到
wgrib2: コマンドが見つかりません