powerman: 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/powerman - from package: powerman

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

On Debian possible default full paths are:

/usr/bin/powerman - from package: powerman

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

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