gmetric: 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/gmetric - from package: ganglia-gmond

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

On Debian possible default full paths are:

/usr/bin/gmetric - from package: ganglia-monitor

You may install the required package with command apt-get install {package}

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