delaunay: 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 Debian possible default full paths are:

/usr/bin/delaunay - from package: libgts-bin

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

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