zyGrib: 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 Debian possible default full paths are:

/usr/bin/zyGrib - from package: zygrib

You may install the required package with command apt-get install {package}

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