wget: 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/bin/wget - from package: wget

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

On Debian possible default full paths are:

/usr/bin/wget - from package: wget

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

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