bel: 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/bel - from package: belier

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

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