oregano: 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/oregano - from package: oregano

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

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