polygraph-aka: 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/polygraph-aka - from package: polygraph

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

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