knews: 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/knews - from package: knews

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

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