macchanger-gtk: 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/sbin/macchanger-gtk - from package: macchanger-gtk

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

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