hackrf_max2837: command not found

Have You tried accessing the binary with the full path?

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/hackrf_max2837 - from package: hackrf

You may install the required package with command apt-get install {package}
Error in other languages:
hackrf_max2837: bevel nie gevind nie
hackrf_max2837: comandă negăsită
hackrf_max2837: comando não encontrado
hackrf_max2837: commande introuvable
hackrf_max2837: command not found
hackrf_max2837: käsku ei ole
hackrf_max2837: không tìm thấy lệnh
hackrf_max2837: komanda nerasta
hackrf_max2837: Kommando nicht gefunden.
hackrf_max2837: kommandot finns inte
hackrf_max2837: komut yok
hackrf_max2837: nie znaleziono polecenia
hackrf_max2837: níor aimsíodh an t-ordú
hackrf_max2837: no se encontró la orden
hackrf_max2837: no s'ha trobat l'ordre
hackrf_max2837: opdracht niet gevonden
hackrf_max2837: parancs nem található
hackrf_max2837: perintah tidak ditemukan
hackrf_max2837: príkaz nenájdený
hackrf_max2837: příkaz nenalezen
hackrf_max2837: команда не найдена
hackrf_max2837: командата не е открита
hackrf_max2837: 命令找不到
hackrf_max2837: コマンドが見つかりません