nvram-wakeup: 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 Debian possible default full paths are:

/usr/sbin/nvram-wakeup - from package: nvram-wakeup

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

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