grdpaste: 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/grdpaste - from package: GMT

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

On Debian possible default full paths are:

/usr/lib/gmt/bin/grdpaste - from package: GMT

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

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