kdf: 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/kdf - from package: kdeutils

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

On Debian possible default full paths are:

/usr/bin/kdf - from package: kdf

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

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