func-grep: 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/func-grep - from package: func

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

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