gmttrack: 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/gmttrack - 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/gmttrack - from package: GMT

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

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