xdx: 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/xdx - from package: xdx

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

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