kf: 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/kf - from package: heimdal-workstation

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

On Debian possible default full paths are:

/usr/bin/kf - from package: heimdal-clients

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

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