cg: 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/cg - from package: cgvg

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

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