pystache3: command not found

Have You tried accessing the binary with the full path?

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/pystache3 - from package: python3-pystache

You may install the required package with command apt-get install {package}
Error in other languages:
pystache3: bevel nie gevind nie
pystache3: comandă negăsită
pystache3: comando não encontrado
pystache3: commande introuvable
pystache3: command not found
pystache3: käsku ei ole
pystache3: không tìm thấy lệnh
pystache3: komanda nerasta
pystache3: Kommando nicht gefunden.
pystache3: kommandot finns inte
pystache3: komut yok
pystache3: nie znaleziono polecenia
pystache3: níor aimsíodh an t-ordú
pystache3: no se encontró la orden
pystache3: no s'ha trobat l'ordre
pystache3: opdracht niet gevonden
pystache3: parancs nem található
pystache3: perintah tidak ditemukan
pystache3: príkaz nenájdený
pystache3: příkaz nenalezen
pystache3: команда не найдена
pystache3: командата не е открита
pystache3: 命令找不到
pystache3: コマンドが見つかりません