rl: command not found

Have You tried accessing the binary with the full path?

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/rl - from package: randomize-lines

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