mydist: 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/share/doc/mh-book/examples/mh/bin/mydist - from package: mh-book

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

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