pydf: 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 CentOS possible default full paths are:

/usr/bin/pydf - from package: pydf

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/pydf - from package: pydf

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

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