finddup: 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/finddup - from package: perforate

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

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