rdup-tr: 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/rdup-tr - from package: rdup

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

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