ioping: 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/ioping - from package: ioping

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

On Debian possible default full paths are:

/usr/bin/ioping - from package: ioping

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

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