nodup: 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/nodup - from package: perforate

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

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