gok: 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/gok - from package: gok

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

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