purge_gids: 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/purge_gids - from package: nfs-ganesha-utils

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

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