brctl: 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 CentOS possible default full paths are:

/usr/sbin/brctl - from package: bridge-utils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/sbin/brctl - from package: bridge-utils

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

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