ceph-client-debug: 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/ceph-client-debug - from package: ceph

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

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