gnunet-fuse: 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-fuse - from package: gnunet-fuse

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

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