br: 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/br - from package: bottlerocket

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

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