gyrus: 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/gyrus - from package: gyrus

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

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