g_bond: 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/g_bond - from package: gromacs

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

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