atheist: 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/atheist - from package: atheist

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

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