nxdir: 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/nxdir - from package: nexus-tools

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

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