disco: 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 CentOS possible default full paths are:

/usr/bin/disco - from package: mono-web

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/disco - from package: mono-devel

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

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