authconfig: 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/authconfig - from package: authconfig-gtk
/usr/sbin/authconfig - from package: authconfig

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

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