packer: 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/packer - from package: cracklib-dicts

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

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