elastix: 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/elastix - from package: elastix

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

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