grunt: 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/grunt - from package: nodejs-grunt-cli

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

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