predator: 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/predator - from package: undertaker

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

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