sphtriangulate: 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/sphtriangulate - 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/sphtriangulate - from package: GMT

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

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