hsmarkdown: 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

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/hsmarkdown - from package: pandoc

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