clone: 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:

/sbin/clone - from package: nut

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

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