rib_xrl_shell_funcs.sh: 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/lib/xorp/bin/rib_xrl_shell_funcs.sh - from package: xorp

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

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