juk: 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/juk - from package: kdemultimedia

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

On Debian possible default full paths are:

/usr/bin/juk - from package: juk

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

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