xd: 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/xd - from package: xd

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

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