ath_info: 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/ath_info - from package: ath_info

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

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