osgplanets: 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/osgplanets - from package: openscenegraph

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

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