tf5: 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/tf5 - from package: tf5

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

Error in other languages:
tf5: bevel nie gevind nie
tf5: comandă negăsită
tf5: comando não encontrado
tf5: commande introuvable
tf5: command not found
tf5: käsku ei ole
tf5: không tìm thấy lệnh
tf5: komanda nerasta
tf5: Kommando nicht gefunden.
tf5: kommandot finns inte
tf5: komut yok
tf5: nie znaleziono polecenia
tf5: níor aimsíodh an t-ordú
tf5: no se encontró la orden
tf5: no s'ha trobat l'ordre
tf5: opdracht niet gevonden
tf5: parancs nem található
tf5: perintah tidak ditemukan
tf5: príkaz nenájdený
tf5: příkaz nenalezen
tf5: команда не найдена
tf5: командата не е открита
tf5: 命令找不到
tf5: コマンドが見つかりません