gammaray: 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/gammaray - from package: gammaray

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

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