xencons: 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/lib/xen-4.4/bin/xencons - from package: xen-utils-4.4

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

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