grog: 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/grog - from package: groff

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

On Debian possible default full paths are:

/usr/bin/grog - from package: groff-base

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

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