ophcrack-cli: 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/ophcrack-cli - from package: ophcrack-cli

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

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