asy: 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/asy - from package: asymptote

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

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