polygraph-dns-cfg: 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/polygraph-dns-cfg - from package: polygraph

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