gnunet-directory: 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/gnunet-directory - from package: gnunet

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

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