moonshot-webp: 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/moonshot-webp - from package: moonshot-ui

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

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