memcached-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/memcached-tool - from package: memcached

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

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