gxps: 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/gxps - from package: grads

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

On Debian possible default full paths are:

/usr/bin/gxps - from package: grads

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

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