avahi-daemon: 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 CentOS possible default full paths are:

/usr/sbin/avahi-daemon - from package: avahi

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/avahi-daemon - from package: avahi-daemon

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

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