obsession-exit: 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/obsession-exit - from package: obsession

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