r2r_show: 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/r2r_show - from package: ruby-ruby2ruby

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

Error in other languages:
r2r_show: bevel nie gevind nie
r2r_show: comandă negăsită
r2r_show: comando não encontrado
r2r_show: commande introuvable
r2r_show: command not found
r2r_show: käsku ei ole
r2r_show: không tìm thấy lệnh
r2r_show: komanda nerasta
r2r_show: Kommando nicht gefunden.
r2r_show: kommandot finns inte
r2r_show: komut yok
r2r_show: nie znaleziono polecenia
r2r_show: níor aimsíodh an t-ordú
r2r_show: no se encontró la orden
r2r_show: no s'ha trobat l'ordre
r2r_show: opdracht niet gevonden
r2r_show: parancs nem található
r2r_show: perintah tidak ditemukan
r2r_show: príkaz nenájdený
r2r_show: příkaz nenalezen
r2r_show: команда не найдена
r2r_show: командата не е открита
r2r_show: 命令找不到
r2r_show: コマンドが見つかりません