airport-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/airport-config - from package: airport-utils

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

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