ask: 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/ask - from package: ask

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

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