fio: 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/fio - from package: fio

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

On Debian possible default full paths are:

/usr/bin/fio - from package: fio

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

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