stop_epsilon_nodes: command not found

Have You tried accessing the binary with the full path?

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/stop_epsilon_nodes - from package: epsilon-bin

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