ceph-monstore-tool: 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-monstore-tool - from package: ceph-test

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

On Debian possible default full paths are:

/usr/lib/ceph/bin/ceph-monstore-tool - from package: ceph-test

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

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