epiphany: 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/epiphany - from package: epiphany-browser

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

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