waf: 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/waf - from package: waf

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

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