altair: 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/altair - from package: simh

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

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