xauth: 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 CentOS possible default full paths are:

/usr/bin/xauth - from package: xorg-x11-xauth

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/xauth - from package: xauth

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

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