revelation: 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/revelation - from package: revelation

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

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