fedora-groupdel: command not found

Have You tried accessing the binary with the full path?

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/sbin/fedora-groupdel - from package: fedora-usermgmt-core

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