psurface-simplify: 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/psurface-simplify - from package: psurface

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

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