polygraph-lx: 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-lx - from package: polygraph

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

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