grind: 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/grind - from package: wordnet-grind

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

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