eos: 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/eos - from package: elk-lapw

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

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