hatop: 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/hatop - from package: hatop

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