gmtstitch: 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/gmtstitch - 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/gmtstitch - from package: GMT

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

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