avra: 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/bin/avra - from package: avra

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

On Debian possible default full paths are:

/usr/bin/avra - from package: avra

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

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