github-markup: 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/bin/github-markup - from package: ruby-github-markup

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

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