rabbitsign: 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/rabbitsign - from package: rabbitsign

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

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