dcbtool: 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/dcbtool - from package: lldpad

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

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