rifle: 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/rifle - from package: ranger

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

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