gri-2.12.23: 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/gri-2.12.23 - from package: gri

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

Error in other languages:
gri-2.12.23: bevel nie gevind nie
gri-2.12.23: comandă negăsită
gri-2.12.23: comando não encontrado
gri-2.12.23: commande introuvable
gri-2.12.23: command not found
gri-2.12.23: käsku ei ole
gri-2.12.23: không tìm thấy lệnh
gri-2.12.23: komanda nerasta
gri-2.12.23: Kommando nicht gefunden.
gri-2.12.23: kommandot finns inte
gri-2.12.23: komut yok
gri-2.12.23: nie znaleziono polecenia
gri-2.12.23: níor aimsíodh an t-ordú
gri-2.12.23: no se encontró la orden
gri-2.12.23: no s'ha trobat l'ordre
gri-2.12.23: opdracht niet gevonden
gri-2.12.23: parancs nem található
gri-2.12.23: perintah tidak ditemukan
gri-2.12.23: príkaz nenájdený
gri-2.12.23: příkaz nenalezen
gri-2.12.23: команда не найдена
gri-2.12.23: командата не е открита
gri-2.12.23: 命令找不到
gri-2.12.23: コマンドが見つかりません