gmtinfo: 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/gmtinfo - 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/gmtinfo - from package: GMT

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

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