mariadb_config: 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/mariadb_config - from package: libmariadb-client-lgpl-dev

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

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