cpu_usage: 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/cpu_usage - from package: libstatgrab-examples

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

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