tlp: 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/tlp - from package: tlp

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

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