btdownloadheadless.bittornado: 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/btdownloadheadless.bittornado - from package: bittornado

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

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