ebook2epub: 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/ebook2epub - from package: ebook2epub

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

Error in other languages:
ebook2epub: bevel nie gevind nie
ebook2epub: comandă negăsită
ebook2epub: comando não encontrado
ebook2epub: commande introuvable
ebook2epub: command not found
ebook2epub: käsku ei ole
ebook2epub: không tìm thấy lệnh
ebook2epub: komanda nerasta
ebook2epub: Kommando nicht gefunden.
ebook2epub: kommandot finns inte
ebook2epub: komut yok
ebook2epub: nie znaleziono polecenia
ebook2epub: níor aimsíodh an t-ordú
ebook2epub: no se encontró la orden
ebook2epub: no s'ha trobat l'ordre
ebook2epub: opdracht niet gevonden
ebook2epub: parancs nem található
ebook2epub: perintah tidak ditemukan
ebook2epub: príkaz nenájdený
ebook2epub: příkaz nenalezen
ebook2epub: команда не найдена
ebook2epub: командата не е открита
ebook2epub: 命令找不到
ebook2epub: コマンドが見つかりません