horst: 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/horst - from package: horst

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

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