tybg: 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/tybg - from package: terminology

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

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