hiredis-example: 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/hiredis-example - from package: hiredis

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

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