Cone6: 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/Cone6 - from package: vtk-examples

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

Error in other languages:
Cone6: bevel nie gevind nie
Cone6: comandă negăsită
Cone6: comando não encontrado
Cone6: commande introuvable
Cone6: command not found
Cone6: käsku ei ole
Cone6: không tìm thấy lệnh
Cone6: komanda nerasta
Cone6: Kommando nicht gefunden.
Cone6: kommandot finns inte
Cone6: komut yok
Cone6: nie znaleziono polecenia
Cone6: níor aimsíodh an t-ordú
Cone6: no se encontró la orden
Cone6: no s'ha trobat l'ordre
Cone6: opdracht niet gevonden
Cone6: parancs nem található
Cone6: perintah tidak ditemukan
Cone6: príkaz nenájdený
Cone6: příkaz nenalezen
Cone6: команда не найдена
Cone6: командата не е открита
Cone6: 命令找不到
Cone6: コマンドが見つかりません